Terms starting with letter a

Color key: WebIDL CSS Markup HTTP

a (value for type attribute of ol element ) §: Defined in HTML
a (markup element) §: Defined in HTML; Referenced in CSS Linked Parameters, execCommand, Attribution Reporting, Prerendering Revamped, Content Security Policy 3, CSS Overflow 5, CSS Syntax 3, CSS Transforms 2, Web Platform Design Principles, EPUB 3.3, EPUB 3.4, File API, HTML Accessibility API Mappings 1.0, ARIA in HTML, Publication Manifest, Referrer Policy, Resource Timing, Selectors 4, SVG 2, WAI-ARIA, WAI-ARIA, WebDriver; Related terms: markup attribute charset, markup attribute coords, markup attribute methods, markup attribute name, markup attribute rev, markup attribute shape, markup attribute urn
a (CSS value for lab() ) §: Defined in CSS Color 5; Referenced in CSS Extensions 1, Filter Effects 1, Selectors 4
a (CSS value for oklab() ) §: Defined in CSS Color 5
a (CSS value for jzazbz() ) §: Defined in CSS Color HDR 1
a (markup element) §: Defined in SVG 2; Referenced in CSS Masking 1; Related terms: markup attribute requiredExtensions, markup attribute systemLanguage, markup attribute xlink:href, markup attribute xlink:title
CSSLab.a (WebIDL attribute) §: Defined in CSS Typed OM 1
CSSOKLab.a (WebIDL attribute) §: Defined in CSS Typed OM 1
DOMMatrix.a (WebIDL attribute) §
DOMMatrixReadOnly.a (WebIDL attribute) §: Defined in Geometry Interfaces 1
DOMMatrix2DInit.a (WebIDL dictionary member) §: Defined in Geometry Interfaces 1
GPUColorDict.a (WebIDL dictionary member) §: Defined in WebGPU
MLBinarySupportLimits.a (WebIDL dictionary member) §: Defined in Web Neural Network API
MLGemmSupportLimits.a (WebIDL dictionary member) §: Defined in Web Neural Network API
MLLogicalNotSupportLimits.a (WebIDL dictionary member) §: Defined in Web Neural Network API
A (value for type attribute of ol element ) §: Defined in HTML
a known definite encoding (concept) §: Defined in HTML; Referenced in XMLHttpRequest
a new promise (concept) §: Defined in Web IDL; Referenced in Cookie Store API, DOM, Fetch, File System, WebXR Anchors, Notifications API, Topics API, requestStorageAccessFor API, Extending Storage Access API to non-cookie storage, The Storage Access API, Storage, Streams, Long Animation Frames API, WebAssembly JavaScript Interface: Content Security Policy, WebAssembly JavaScript Interface: ESM Integration, WebAssembly JavaScript Interface: Exception Handling, WebAssembly JavaScript Interface: Promise Integration, WebAssembly JavaScript Interface: JS String Builtins, WebAssembly JavaScript Interface: Type Reflection, Web Speech API, Web Bluetooth, Web Bluetooth Scanning, Translator and Language Detector APIs, Writing Assistance APIs, Direct Sockets API, EyeDropper API, Fenced Frame, File System Access, Handwriting Recognition API, Idle Detection API, JS Self-Profiling API, Local Font Access API, Prerendering Revamped, Observable, Relinquishing Permissions, Prioritized Task Scheduling, Web Serial API, Shared Storage API, Storage Buckets API, Private State Token API, Protected Audience, User-Agent Client Hints, Web Smart Card API, Device Attributes API, Managed Configuration API, WebHID API, WebUSB API, Badging API, Battery Status API, Clipboard API and events, Compute Pressure 1, Contact Picker API, Credential Management 1, CSS View Transitions 1, CSS View Transitions 2, Gamepad, Indexed DB 3.0, Media Queries 5, Device Orientation and Motion, Payment Request API, Permissions, Picture-in-Picture, Pointer Lock 2.0, Privacy-Preserving Attribution 1, Push API, Screen Orientation, Screen Wake Lock API, Service Workers, WebAssembly JavaScript Interface, WebAssembly Web API, Web Animations, Web Animations 2, Web Locks API, Web Share API, Web Authentication, WebDriver, WebGPU, Web Neural Network API, WebRTC Encoded Transform, WebXR Hit Test, WebXR Lighting Estimation API 1, WebXR Device API, Window Management
a priori authenticated URL (concept) §: Defined in Mixed Content; Referenced in HTML, Clear Site Data, Secure Contexts
a promise rejected with (concept) §: Defined in Web IDL; Referenced in Cookie Store API, Fetch, File System, HTML, Streams, Web Bluetooth, Web Bluetooth Scanning, Translator and Language Detector APIs, Writing Assistance APIs, Digital Goods API, File System Access, Handwriting Recognition API, Idle Detection API, JS Self-Profiling API, Prerendering Revamped, Observable, Requesting Permissions, Relinquishing Permissions, Shared Storage API, Storage Buckets API, WebUSB API, Badging API, Compute Pressure 1, Contact Picker API, Credential Management 1, Federated Credential Management API, Gamepad, MediaStream Image Capture, Indexed DB 3.0, MediaStreamTrack Insertable Media Processing using Streams, Media Queries 5, Media Session, Payment Request API, Permissions, Privacy-Preserving Attribution 1, Screen Orientation, Screen Wake Lock API, Secure Payment Confirmation, Service Workers, Web Locks API, Web Share API, Web Audio API, Web Audio API 1.1, Web Authentication, WebCodecs, WebGPU, WebTransport
a promise resolved with (concept) §: Defined in Web IDL; Referenced in File System, HTML, Streams, Writing Assistance APIs, Digital Goods API, Direct Sockets API, File System Access, Handwriting Recognition API, Observable, Web Serial API, WebUSB API, Credential Management 1, CSS View Transitions 1, CSS View Transitions 2, MediaStreamTrack Insertable Media Processing using Streams, Privacy-Preserving Attribution 1, Screen Wake Lock API, Service Workers, Web Animations, Web Authentication, WebRTC Encoded Transform, WebTransport
"a-rate" (value for AutomationRate WebIDL enumeration) §: Defined in Web Audio API , Web Audio API 1.1
a1lx (concept for AV1LayeredImageIndexingProperty ) §: Defined in AVIF
a1op (concept for OperatingPointSelectorProperty ) §: Defined in AVIF
A3 (CSS value for <page-size> ) §: Defined in CSS Paged Media 3
A4 (CSS value for <page-size> ) §: Defined in CSS Paged Media 3
A5 (CSS value for <page-size> ) §: Defined in CSS Paged Media 3
a98-rgb (CSS value for color() ) §: Defined in CSS Color 4; Referenced in CSS Color 5
"aac" (value for AacBitstreamFormat WebIDL enumeration) §: Defined in AAC WebCodecs Registration
AudioEncoderConfig.aac (WebIDL dictionary member) §: Defined in AAC WebCodecs Registration
AacBitstreamFormat (WebIDL enumeration) §: Defined in AAC WebCodecs Registration; Related terms: value aac, value adts; see also WebIDLPedia
AacEncoderConfig (WebIDL dictionary) §: Defined in AAC WebCodecs Registration; Related terms: AacEncoderConfig.format; see also WebIDLPedia
abbr (markup element) §: Defined in HTML; Referenced in Web Platform Design Principles, HTML Accessibility API Mappings 1.0, ARIA in HTML; Related terms: markup attribute title
abbr (markup attribute for th ) §: Defined in HTML; Referenced in HTML Accessibility API Mappings 1.0
abbr (markup attribute for td ) §: Defined in HTML
HTMLTableCellElement.abbr (WebIDL attribute) §: Defined in HTML
Abjad (concept) §: Defined in Internationalization Glossary
abort (event for AbortSignal ) §: Defined in DOM; Referenced in Observable
abort (concept for fetch controller ) §: Defined in Fetch; Referenced in HTML, Prefetch, Protected Audience, Service Workers, XMLHttpRequest
abort (event for HTMLMediaElement ) §: Defined in HTML
abort (concept for WritableStream ) §: Defined in Streams; Referenced in Direct Sockets API, Web Serial API
abort (event for FileReader ) §: Defined in File API
abort (event for IDBTransaction ) §: Defined in Indexed DB 3.0
abort (event) §: Defined in Media Source Extensions™
abort (event for XMLHttpRequestEventTarget ) §: Defined in XMLHttpRequest
ObservableInspector.abort (WebIDL dictionary member) §: Defined in Observable
UnderlyingSink.abort (WebIDL dictionary member) §: Defined in Streams
abort a running script (concept) §: Defined in HTML; Referenced in Service Workers
abort reason (concept for AbortSignal ) §: Defined in DOM; Referenced in Fetch, Streams, Web NFC, Translator and Language Detector APIs, Writing Assistance APIs, Direct Sockets API, EyeDropper API, Idle Detection API, Observable, Prioritized Task Scheduling, Web Serial API, Protected Audience, Web Smart Card API, Credential Management 1, Geolocation Sensor, Web Locks API, Web Authentication, WebTransport
Abort the fetch() call (concept) §: Defined in Fetch
abort the update (concept) §: Defined in Payment Request API
abort when (concept) §: Defined in Infra; Referenced in Fetch, Private Aggregation API, Web Bluetooth, Writing Assistance APIs, Background Fetch, Prefetch, Service Workers, WebDriver, Web Neural Network API, WebTransport
DOMException.ABORT_ERR (WebIDL constant) §: Defined in Web IDL
BackgroundFetchRegistration.abort() (WebIDL operation) §: Defined in Background Fetch
FileReader.abort() (WebIDL operation) §: Defined in File API
IDBTransaction.abort() (WebIDL operation) §: Defined in Indexed DB 3.0
PaymentRequest.abort() (WebIDL operation) §: Defined in Payment Request API
SourceBuffer.abort() (WebIDL operation) §: Defined in Media Source Extensions™
SpeechRecognition.abort() (WebIDL operation) §: Defined in Web Speech API; Referenced in Prerendering Revamped
XMLHttpRequest.abort() (WebIDL operation) §: Defined in XMLHttpRequest
AbortController.abort(reason) (WebIDL operation) §: Defined in DOM; Referenced in Web Platform Design Principles
AbortSignal.abort(reason) (WebIDL operation) §: Defined in DOM
WritableStream.abort(reason) (WebIDL operation) §: Defined in Streams; Referenced in Direct Sockets API, Web Serial API, WebTransport
WritableStreamDefaultWriter.abort(reason) (WebIDL operation) §: Defined in Streams; Referenced in Direct Sockets API, Web Serial API, WebTransport
abortAlgorithm (concept for set up of WritableStream interface ) §: Defined in Streams; Referenced in File System, Direct Sockets API, Web Serial API, MediaStreamTrack Insertable Media Processing using Streams, WebTransport
AbortController (WebIDL interface) §: Defined in DOM; Referenced in HTML, Streams, Web Bluetooth, Writing Assistance APIs, Observable, Prioritized Task Scheduling, Web Platform Design Principles, Service Workers, Web Authentication, WebRTC Encoded Transform; Related terms: concept signal, concept signal abort, AbortController.signal, new AbortController(), AbortController.abort(reason); see also WebIDLPedia
new AbortController() (WebIDL constructor) §: Defined in DOM
aborted (concept for AbortSignal ) §: Defined in DOM; Referenced in Fetch, HTML, Streams, Web NFC, Web Bluetooth, Translator and Language Detector APIs, Writing Assistance APIs, Direct Sockets API, Idle Detection API, Observable, Prioritized Task Scheduling, Web Serial API, Protected Audience, Web Smart Card API, Credential Management 1, Web Platform Design Principles, Geolocation Sensor, Web Locks API, Web Authentication, WebRTC Encoded Transform
"aborted" (value for SpeechRecognitionErrorCode WebIDL enumeration) §: Defined in Web Speech API
"aborted" (value for BackgroundFetchFailureReason WebIDL enumeration) §: Defined in Background Fetch
AbortSignal.aborted (WebIDL attribute) §: Defined in DOM; Referenced in EyeDropper API
aborted flag (concept for response ) §: Defined in Fetch; Referenced in Service Workers, XMLHttpRequest
aborted network error (concept) §: Defined in Fetch; Referenced in HTML, Background Fetch
AbortError (exception) §: Defined in Web IDL; Referenced in DOM, Fetch, File System, HTML, Web NFC, Web Bluetooth, Writing Assistance APIs, EyeDropper API, File System Access, Web Smart Card API, WebHID API, WebUSB API, Audio Output Devices API, Compute Pressure 1, CSS View Transitions 1, CSS View Transitions 2, Indexed DB 3.0, Media Capture and Streams, Viewport Capture, Payment Request API, Push API, Screen Capture, Screen Orientation, Secure Payment Confirmation, Service Workers, Web Animations, Web Locks API, Web Share API, Web Authentication, WebCodecs, WebGPU, Web MIDI API, WebTransport, WebXR Device API, XMLHttpRequest
AbortSignal (WebIDL interface) §: Defined in DOM; Referenced in Fetch, HTML, Streams, Web NFC, Web Bluetooth, Translator and Language Detector APIs, Writing Assistance APIs, EyeDropper API, Idle Detection API, Observable, Prioritized Task Scheduling, Protected Audience, Web Smart Card API, Credential Management 1, Web Platform Design Principles, Geolocation Sensor, Web Locks API, Web Authentication; Related terms: concept abort reason, concept aborted, concept add, concept onabort, concept remove, AbortSignal.aborted, AbortSignal.onabort, AbortSignal.reason, event abort, AbortSignal.abort(reason), AbortSignal.any(signals), AbortSignal.throwIfAborted(), AbortSignal.timeout(milliseconds); see also WebIDLPedia
[[AbortSteps]] (algorithm for WritableStreamDefaultController ) §: Defined in Streams
[[AbortSteps]] (algorithm for WritableStreamController ) §: Defined in Streams
abrupt completion (concept for ECMAScript ) §: Defined in ECMAScript
MLOpSupportLimits.abs (WebIDL dictionary member) §: Defined in Web Neural Network API
abs() (CSS function) §: Defined in CSS Values 4
MLGraphBuilder.abs(input, options) (WebIDL operation) §: Defined in Web Neural Network API
Math.abs(x) (WebIDL operation) §: Defined in ECMAScript
"absent" (value for SmartCardConnectionState WebIDL enumeration) §: Defined in Web Smart Card API
absolute (CSS value for position ) §: Defined in CSS Positioned Layout 3 , CSS 2; Referenced in Quirks Mode, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2025, CSS Positioned Layout 4, CSS Scroll Anchoring 1, WebVTT: The Web Video Text Tracks Format
absolute (CSS value for voice-pitch ) §: Defined in CSS Speech 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
absolute (CSS value for voice-range ) §: Defined in CSS Speech 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
DeviceOrientationEvent.absolute (WebIDL attribute) §: Defined in Device Orientation and Motion
DeviceOrientationEventInit.absolute (WebIDL dictionary member) §: Defined in Device Orientation and Motion
absolute color (concept) §: Defined in CSS Color 4 , CSS Color 5; Referenced in CSS Fonts 4
Absolute D65 CIE XYZ (concept) §: Defined in CSS Color HDR 1
absolute position (concept) §: Defined in CSS Positioned Layout 3; Referenced in Pointer-driven Animations, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Box Alignment 3, CSS Anchor Positioning, CSS Display 3, CSS Display 4, CSS Inline Layout 3, CSS Multicol 1, CSS Multicol 2, CSS Overflow 4, CSS Positioned Layout 4, CSS Sizing 4, Scroll-driven Animations
absolute positioning containing block (concept) §: Defined in CSS Positioned Layout 3; Referenced in CSS Containment 1, CSS Containment 2, CSS Positioned Layout 4, CSS View Transitions 1, CSS View Transitions 2
absolute positioning layout (concept) §: Defined in CSS Positioned Layout 3
absolute scroll (concept) §: Defined in CSS Scroll Snap 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
absolute-colorimetric (CSS value for rendering-intent descriptor of @color-profile @rule ) §: Defined in CSS Color 5
absolute-orientation virtual sensor type (concept) §: Defined in Device Orientation and Motion; Referenced in Orientation Sensor
absolute-position containing block (concept) §: Defined in CSS Positioned Layout 3
<absolute-size> (CSS type) §: Defined in CSS 2; Referenced in CSS Fonts 4, CSS Typed OM 1
absolute-URL string (concept) §: Defined in URL; Referenced in Network Reporting API, Web NFC, CSSOM, EPUB 3.3, EPUB 3.4, Payment Method Manifest, Publication Manifest, Verifiable Credentials Data Model v2.0
absolute-URL-with-fragment string (concept) §: Defined in URL; Referenced in Fetch, EPUB 3.3, EPUB 3.4, Publication Manifest
AbsoluteOrientationSensor (WebIDL interface) §: Defined in Orientation Sensor; Related terms: new AbsoluteOrientationSensor(sensorOptions); see also WebIDLPedia
new AbsoluteOrientationSensor(sensorOptions) (WebIDL constructor) §: Defined in Orientation Sensor
Abstract Closure (concept for ECMAScript ) §: Defined in ECMAScript; Referenced in HTML, ECMAScript® 2026 Internationalization API, Source map format, ECMAScript Async Explicit Resource Management, Deferred Imports Evaluation, ECMAScript Explicit Resource Management, Iterator Sequencing, Source Phase Imports, Web IDL
abstract dimensions (concept) §: Defined in CSS Writing Modes 3 , CSS Writing Modes 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Layout API 1
abstract operation HostGrowSharedArrayBuffer (concept) §: Defined in WebAssembly JavaScript Interface: Threading
abstract operation HostResizeArrayBuffer (concept) §: Defined in WebAssembly JavaScript Interface: Content Security Policy , WebAssembly JavaScript Interface: ESM Integration , WebAssembly JavaScript Interface: Promise Integration , WebAssembly JavaScript Interface: JS String Builtins , WebAssembly JavaScript Interface: Threading , WebAssembly JavaScript Interface
AbstractRange (WebIDL interface) §: Defined in DOM; Referenced in CSS Custom Highlight API 1; Related terms: AbstractRange.collapsed, AbstractRange.endContainer, AbstractRange.endOffset, AbstractRange.startContainer, AbstractRange.startOffset; see also WebIDLPedia
AbstractWorker (WebIDL interface) §: Defined in HTML; Referenced in Service Workers; Related terms: AbstractWorker.onerror, event error; see also WebIDLPedia
Abugida (concept) §: Defined in Internationalization Glossary
MLContext.[[accelerated]] (internal slot) §
MLContext.[[accelerated]] (internal slot) §: Defined in Web Neural Network API , Web Neural Network API
MLContextOptions.accelerated (WebIDL dictionary member) §: Defined in Web Neural Network API
DeviceMotionEvent.acceleration (WebIDL attribute) §: Defined in Device Orientation and Motion
DeviceMotionEventInit.acceleration (WebIDL dictionary member) §: Defined in Device Orientation and Motion
DeviceMotionEvent.accelerationIncludingGravity (WebIDL attribute) §: Defined in Device Orientation and Motion
DeviceMotionEventInit.accelerationIncludingGravity (WebIDL dictionary member) §: Defined in Device Orientation and Motion
Accelerometer (WebIDL interface) §: Defined in Accelerometer; Referenced in Orientation Sensor; Related terms: Accelerometer.x, Accelerometer.y, Accelerometer.z, new Accelerometer(options); see also WebIDLPedia
"accelerometer" (permission name) §: Defined in Device Orientation and Motion; Referenced in Accelerometer
accelerometer virtual sensor type (concept) §: Defined in Device Orientation and Motion; Referenced in Accelerometer
new Accelerometer(options) (WebIDL constructor) §: Defined in Accelerometer
AccelerometerLocalCoordinateSystem (WebIDL enumeration) §: Defined in Accelerometer; Related terms: value device, value screen; see also WebIDLPedia
AccelerometerSensorOptions (WebIDL dictionary) §: Defined in Accelerometer; Related terms: AccelerometerSensorOptions.referenceFrame; see also WebIDLPedia
accent (markup attribute for mover, munder element, munderover element ) §: Defined in MathML Core
accent-color (CSS property) §: Defined in CSS User Interface 4; Referenced in CSS Color 4, CSS Color Adjustment 1, CSS Form Control Styling 1, CSS Text Decoration 4; Related terms: CSS value auto
AccentColor (CSS value for <color>, <system-color> type ) §: Defined in CSS Color 4; Referenced in CSS Color Adjustment 1
AccentColorText (CSS value for <color>, <system-color> type ) §: Defined in CSS Color 4; Referenced in CSS Color Adjustment 1
accentunder (markup attribute for mover, munder element, munderover element ) §: Defined in MathML Core
accept (markup attribute for input ) §: Defined in HTML; Referenced in Web Platform Design Principles, HTML Accessibility API Mappings 1.0, HTML Media Capture
accept (markup attribute for form ) §: Defined in HTML
FilePickerAcceptType.accept (WebIDL dictionary member) §: Defined in File System Access
HTMLInputElement.accept (WebIDL attribute) §: Defined in HTML; Referenced in File and Directory Entries API
Accept-CH cache (concept) §: Defined in Client Hints Infrastructure; Referenced in Clear Site Data
accept-charset (markup attribute for form ) §: Defined in HTML; Referenced in HTML Accessibility API Mappings 1.0
acceptable anchor element (concept) §: Defined in CSS Anchor Positioning
BluetoothLEScan.acceptAllAdvertisements (WebIDL attribute) §: Defined in Web Bluetooth Scanning
BluetoothLEScanOptions.acceptAllAdvertisements (WebIDL dictionary member) §: Defined in Web Bluetooth Scanning
BluetoothLEScanPermissionDescriptor.acceptAllAdvertisements (WebIDL dictionary member) §: Defined in Web Bluetooth Scanning
BluetoothPermissionDescriptor.acceptAllDevices (WebIDL dictionary member) §: Defined in Web Bluetooth
RequestDeviceOptions.acceptAllDevices (WebIDL dictionary member) §: Defined in Web Bluetooth
HTMLFormElement.acceptCharset (WebIDL attribute) §: Defined in HTML
"accepted" (value for AppBannerPromptOutcome WebIDL enumeration) §: Defined in Manifest Incubations
accepted @position-try properties (concept) §: Defined in CSS Anchor Positioning
NodeFilter.acceptNode(node) (WebIDL operation) §: Defined in DOM
GPUStorageTextureBindingLayout.access (WebIDL dictionary member) §: Defined in WebGPU
Access-Control-Allow-Credentials: (HTTP header) §: Defined in Fetch; Referenced in requestStorageAccessFor API, Beacon
Access-Control-Allow-Headers: (HTTP header) §: Defined in Fetch; Referenced in Beacon
Access-Control-Allow-Methods: (HTTP header) §: Defined in Fetch
Access-Control-Allow-Origin: (HTTP header) §: Defined in Fetch; Referenced in Beacon
Access-Control-Expose-Headers: (HTTP header) §: Defined in Fetch
Access-Control-Max-Age: (HTTP header) §: Defined in Fetch
Access-Control-Request-Headers: (HTTP header) §: Defined in Fetch; Referenced in Propagation format for distributed context: Baggage, Trace Context 2
Access-Control-Request-Method: (HTTP header) §: Defined in Fetch
Accessibility API (concept) §: Defined in WAI-ARIA , WAI-ARIA
accessibility child (concept) §: Defined in WAI-ARIA , WAI-ARIA
accessibility descendant (concept) §: Defined in WAI-ARIA , WAI-ARIA
accessibility parent (concept) §: Defined in WAI-ARIA , WAI-ARIA
accessibility subtree (concept) §: Defined in Core Accessibility API Mappings 1.2
Accessibility Tree (concept) §: Defined in WAI-ARIA , WAI-ARIA
Accessible Description (concept) §: Defined in Accessible Name and Description Computation 1.2
Accessible Name (concept) §: Defined in Accessible Name and Description Computation 1.2
Accessible object (concept) §: Defined in WAI-ARIA , WAI-ARIA
HTMLElement.accessKey (WebIDL attribute) §: Defined in HTML
accesskey (markup attribute for html-global ) §: Defined in HTML; Referenced in HTML Accessibility API Mappings 1.0, SVG 2
HTMLElement.accessKeyLabel (WebIDL attribute) §: Defined in HTML
accessor property (concept for ECMAScript ) §: Defined in ECMAScript; Referenced in HTML, Streams, ECMAScript® 2026 Internationalization API, Source map format, ES Array.fromAsync, Deferred Imports Evaluation, Intl.DurationFormat, Intl Locale Info, Iterator Sequencing, JSON.parse source text access, ShadowRealm API, Temporal, Web IDL, Observable
DisconnectedAccount.account_id (WebIDL dictionary member) §: Defined in Federated Credential Management API
IdentityProviderAPIConfig.account_label (WebIDL dictionary member) §: Defined in Federated Credential Management API
IdentityCredentialDisconnectOptions.accountHint (WebIDL dictionary member) §: Defined in Federated Credential Management API
IdentityResolveOptions.accountId (WebIDL dictionary member) §: Defined in Federated Credential Management API
IdentityProviderAccountList.accounts (WebIDL dictionary member) §: Defined in Federated Credential Management API
IdentityProviderAPIConfig.accounts_endpoint (WebIDL dictionary member) §: Defined in Federated Credential Management API
IdentityProviderWellKnown.accounts_endpoint (WebIDL dictionary member) §: Defined in Federated Credential Management API
accumulate (markup attribute for animate ) §: Defined in SVG Animations 2; Referenced in SVG 2
"accumulate" (value for CompositeOperation, CompositeOperationOrAuto enumeration WebIDL enumerations) §: Defined in Web Animations
"accumulate" (value for IterationCompositeOperation WebIDL enumeration) §: Defined in Web Animations 2
accumulation for one-based values (concept) §: Defined in CSS Transforms 2
accuracy (WebIDL attribute for geolocation override ) §: Defined in WebDriver BiDi
GeolocationCoordinates.accuracy (WebIDL attribute) §: Defined in Geolocation
GeolocationSensor.accuracy (WebIDL attribute) §: Defined in Geolocation Sensor
GeolocationSensorReading.accuracy (WebIDL dictionary member) §: Defined in Geolocation Sensor
acos() (CSS function) §: Defined in CSS Values 4
Math.acos(x) (WebIDL operation) §: Defined in ECMAScript
Math.acosh(x) (WebIDL operation) §: Defined in ECMAScript
AcquireReadableStreamBYOBReader (algorithm) §: Defined in Streams
AcquireReadableStreamDefaultReader (algorithm) §: Defined in Streams
AcquireWritableStreamDefaultWriter (algorithm) §: Defined in Streams
acronym (markup element) §: Defined in HTML; Referenced in Web Platform Design Principles
action (markup attribute for button, form element ) §: Defined in HTML; Referenced in Web Platform Design Principles, HTML Accessibility API Mappings 1.0, Mixed Content
CaptureActionEvent.action (WebIDL attribute) §: Defined in The Capture-Handle Actions Mechanism
CaptureActionEventInit.action (WebIDL dictionary member) §: Defined in The Capture-Handle Actions Mechanism
HTMLFormElement.action (WebIDL attribute) §: Defined in HTML
MediaSessionActionDetails.action (WebIDL dictionary member) §: Defined in Media Session
NotificationAction.action (WebIDL dictionary member) §: Defined in Notifications API; Referenced in Push API
NotificationEvent.action (WebIDL attribute) §: Defined in Notifications API
NotificationEventInit.action (WebIDL dictionary member) §: Defined in Notifications API
actions (concept for notification ) §: Defined in Notifications API; Referenced in Push API
Notification.actions (WebIDL attribute) §: Defined in Notifications API
NotificationOptions.actions (WebIDL dictionary member) §: Defined in Notifications API; Referenced in Push API
actiontype (markup attribute for maction ) §: Defined in MathML Core
activate (event for ServiceWorkerGlobalScope ) §: Defined in Service Workers
Activate a sensor object (concept) §: Defined in Generic Sensor API
HTMLPortalElement.activate(options) (WebIDL operation) §: Defined in Portals
DeferredRequestInit.activateAfter (WebIDL dictionary member) §: Defined in Fetch
"activated" (value for ServiceWorkerState WebIDL enumeration) §: Defined in Service Workers
FetchLaterResult.activated (WebIDL attribute) §: Defined in Fetch
Sensor.activated (WebIDL attribute) §: Defined in Generic Sensor API
"activating" (value for ServiceWorkerState WebIDL enumeration) §: Defined in Service Workers
activation (concept for user navigation involvement ) §: Defined in HTML
Navigation.activation (WebIDL attribute) §: Defined in HTML
PageSwapEvent.activation (WebIDL attribute) §: Defined in HTML; Referenced in CSS View Transitions 2
PageSwapEventInit.activation (WebIDL dictionary member) §: Defined in HTML
activation behavior (concept for EventTarget ) §: Defined in DOM; Referenced in HTML, Portals, SVG 2, UI Events
MLGruCellOptions.activations (WebIDL dictionary member) §: Defined in Web Neural Network API
MLGruOptions.activations (WebIDL dictionary member) §: Defined in Web Neural Network API
MLLstmCellOptions.activations (WebIDL dictionary member) §: Defined in Web Neural Network API
MLLstmOptions.activations (WebIDL dictionary member) §: Defined in Web Neural Network API
PerformanceNavigationTiming.activationStart (WebIDL attribute) §: Defined in Prerendering Revamped
:active (CSS selector) §: Defined in CSS 2 , Selectors 3 , Selectors 4; Referenced in Quirks Mode, CSS Snapshot 2022, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Snapshot 2025, CSS Overflow 5, CSS User Interface 4
"active" (value for UserIdleState WebIDL enumeration) §: Defined in Idle Detection API
"active" (value for ClientLifecycleState WebIDL enumeration) §: Defined in Page Lifecycle
"active" (value for AudioSessionState WebIDL enumeration) §: Defined in Audio Session
"active" (value for IdentityCredentialRequestOptionsMode WebIDL enumeration) §: Defined in Federated Credential Management API
active (CSS value for forced-colors descriptor of @media @rule ) §: Defined in Media Queries 5
active (concept for ExtendableEvent ) §: Defined in Service Workers; Referenced in Background Fetch, WebXR Hand Input 1
"active" (value for AnimationReplaceState WebIDL enumeration) §: Defined in Web Animations
"active" (value for AnimationReplacedState WebIDL enumeration) §: Defined in Web Animations
"active" (value for RTCIceTcpCandidateType WebIDL enumeration) §: Defined in WebRTC 1.0
BluetoothLEScan.active (WebIDL attribute) §: Defined in Web Bluetooth Scanning
MediaStream.active (WebIDL attribute) §: Defined in Media Capture and Streams
RTCOutboundRtpStreamStats.active (WebIDL dictionary member) §: Defined in WebRTC Statistics
RTCRtpEncodingParameters.active (WebIDL dictionary member) §: Defined in WebRTC 1.0; Referenced in WebRTC Encoded Transform
ServiceWorkerRegistration.active (WebIDL attribute) §: Defined in Service Workers
Subscriber.active (WebIDL attribute) §: Defined in Observable
active BiDi sessions (concept) §: Defined in WebDriver BiDi
active browsing context (concept for navigable ) §: Defined in HTML; Referenced in Document Picture-in-Picture, Fenced Frame, Prefetch, Prerendering Revamped, Service Workers, WebDriver BiDi, WebDriver
active custom element constructor map (concept for similar-origin window agent ) §: Defined in HTML; Referenced in DOM
VideoDecoder.[[active decoder config]] (internal slot) §: Defined in WebCodecs
active document (concept for navigable ) §: Defined in HTML; Referenced in Compatibility, Fetch, Fullscreen API, Topics API, Navigational-Tracking Mitigations, requestStorageAccessFor API, The Storage Access API, Login Status API, Long Animation Frames API, Web Bluetooth, Iframe credentialless, Attribution Reporting, Document Picture-in-Picture, Fenced Frame, Manifest Incubations, Prefetch, Prerendering Revamped, URL Fragment Text Directives, Shared Storage API, Web App Launch Handler API, Web Application Manifest, Clear Site Data, Credential Management 1, CSS Spatial Navigation 1, CSSOM View, Device Posture API, Federated Credential Management API, Generic Sensor API, GPC, Largest Contentful Paint, Long Tasks API, Viewport Capture, Mixed Content, Device Orientation and Motion, Permissions Policy, Pointer Lock 2.0, Reporting API, Screen Orientation, Selection API, Service Workers, WebDriver BiDi, WebXR Device API, Window Management
AudioEncoder.[[active encoder config]] (internal slot) §: Defined in WebCodecs
VideoEncoder.[[active encoder config]] (internal slot) §: Defined in WebCodecs
active function object (concept for ECMAScript ) §: Defined in ECMAScript; Referenced in HTML, ECMAScript® 2026 Internationalization API, ECMAScript Async Explicit Resource Management, ECMAScript Explicit Resource Management, JSON.parse source text access, ShadowRealm API
VideoEncoder.[[active orientation]] (internal slot) §: Defined in WebCodecs
AudioEncoder.[[active output config]] (internal slot) §: Defined in WebCodecs
VideoEncoder.[[active output config]] (internal slot) §: Defined in WebCodecs
active phase (concept for animation effect ) §: Defined in Web Animations; Referenced in CSS Animations 2, Web Animations 2
active sandboxing flag set (concept for Document ) §: Defined in HTML; Referenced in The Storage Access API, Fenced Frame, Prerendering Revamped, Protected Audience, Content Security Policy 3, Pointer Lock 2.0, Presentation API
active script or module (concept for ECMAScript ) §: Defined in ECMAScript; Referenced in Source Phase Imports
active service worker (concept for environment ) §: Defined in HTML; Referenced in Prefetch, Service Workers
active speculative HTML parser (concept) §: Defined in HTML
active timeline (concept) §: Defined in Web Animations
active view transition (concept for document ) §: Defined in CSS View Transitions 2
active window (concept for navigable ) §: Defined in HTML; Referenced in Web Bluetooth, Document Picture-in-Picture, Fenced Frame, Prefetch, Prerendering Revamped, Shared Storage API, Device Orientation and Motion, Presentation API, Remote Playback API, WebDriver BiDi
active worker (concept for service worker registration ) §: Defined in Service Workers; Referenced in HTML, Notifications API, Background Fetch, Content Index, Web Periodic Background Synchronization
:active-view-transition (CSS selector) §: Defined in CSS View Transitions 2
:active-view-transition-type() (CSS selector) §: Defined in CSS View Transitions 2
BluetoothRemoteGATTServer.[[activeAlgorithms]] (internal slot) §: Defined in Web Bluetooth
ActiveBorder (concept) §: Defined in CSS Color 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
ActiveBorder (CSS value for <color>, <deprecated-color> type ) §: Defined in CSS Color 4
ActiveCaption (concept) §: Defined in CSS Color 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
ActiveCaption (CSS value for <color>, <deprecated-color> type ) §: Defined in CSS Color 4
TextTrack.activeCues (WebIDL attribute) §: Defined in HTML
ComputedEffectTiming.activeDuration (WebIDL dictionary member) §
ComputedEffectTiming.activeDuration (WebIDL dictionary member) §: Defined in Web Animations , Web Animations 2
DocumentOrShadowRoot.activeElement (WebIDL attribute) §: Defined in HTML; Referenced in CSS Overflow 5
SmartCardConnectResult.activeProtocol (WebIDL dictionary member) §: Defined in Web Smart Card API
Bluetooth.[[activeScans]] (internal slot) §: Defined in Web Bluetooth Scanning
MediaSource.activeSourceBuffers (WebIDL attribute) §: Defined in Media Source Extensions™
ResizeObserver.[[activeTargets]] (internal slot) §: Defined in Resize Observer
ActiveText (CSS value for <color>, <system-color> type ) §: Defined in CSS Color 4; Referenced in CSS Color Adjustment 1
Document.activeViewTransition (WebIDL attribute) §: Defined in CSS View Transitions 2
Element.activeViewTransition (WebIDL attribute) §: Defined in CSS View Transitions 2
actual value (concept) §: Defined in CSS Cascading 3 , CSS Cascading 4 , CSS Cascading 5; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Color 5, CSS Values 3, CSS Values 4, Web Platform Design Principles
TextMetrics.actualBoundingBoxAscent (WebIDL attribute) §: Defined in HTML
TextMetrics.actualBoundingBoxDescent (WebIDL attribute) §: Defined in HTML
TextMetrics.actualBoundingBoxLeft (WebIDL attribute) §: Defined in HTML
TextMetrics.actualBoundingBoxRight (WebIDL attribute) §: Defined in HTML
GenerateBidOutput.ad (WebIDL dictionary member) §: Defined in Protected Audience
Ad-Auction-Additional-Bid: (HTTP header) §: Defined in Protected Audience
Ad-Auction-Allow-Trusted-Scoring-Signals-From: (HTTP header) §: Defined in Protected Audience
Ad-Auction-Allowed: (HTTP header) §: Defined in Protected Audience
Ad-Auction-Result: (HTTP header) §: Defined in Protected Audience
Ad-Auction-Result-Nonce: (HTTP header) §: Defined in Protected Audience
Ad-Auction-Signals: (HTTP header) §: Defined in Protected Audience
[[adapter]] (internal slot for device ) §: Defined in WebGPU
GPUAdapter.[[adapter]] (internal slot) §: Defined in WebGPU
GPUDevice.adapterInfo (WebIDL attribute) §: Defined in WebGPU
Navigator.adAuctionComponents(numAdComponents) (WebIDL operation) §: Defined in Fenced Frame
AdAuctionData (WebIDL dictionary) §: Defined in Protected Audience; Related terms: AdAuctionData.request, AdAuctionData.requestId, AdAuctionData.requests; see also WebIDLPedia
AdAuctionDataBuyerConfig (WebIDL dictionary) §: Defined in Protected Audience; Related terms: AdAuctionDataBuyerConfig.targetSize; see also WebIDLPedia
AdAuctionDataConfig (WebIDL dictionary) §: Defined in Protected Audience; Related terms: AdAuctionDataConfig.coordinatorOrigin, AdAuctionDataConfig.perBuyerConfig, AdAuctionDataConfig.requestSize, AdAuctionDataConfig.seller, AdAuctionDataConfig.sellers; see also WebIDLPedia
HTMLIFrameElement.adAuctionHeaders (WebIDL attribute) §: Defined in Protected Audience
RequestInit.adAuctionHeaders (WebIDL dictionary member) §: Defined in Protected Audience
adauctionheaders (markup attribute for iframe ) §: Defined in Protected Audience
AdAuctionOneSeller (WebIDL dictionary) §: Defined in Protected Audience; Related terms: AdAuctionOneSeller.coordinatorOrigin, AdAuctionOneSeller.seller; see also WebIDLPedia
AdAuctionPerSellerData (WebIDL dictionary) §: Defined in Protected Audience; Related terms: AdAuctionPerSellerData.error, AdAuctionPerSellerData.request, AdAuctionPerSellerData.seller; see also WebIDLPedia
GenerateBidInterestGroup.adComponents (WebIDL dictionary member) §: Defined in Protected Audience
GenerateBidOutput.adComponents (WebIDL dictionary member) §: Defined in Protected Audience
ScoringBrowserSignals.adComponents (WebIDL dictionary member) §: Defined in Protected Audience
ScoringBrowserSignals.adComponentsCreativeScanningMetadata (WebIDL dictionary member) §: Defined in Protected Audience
BiddingBrowserSignals.adComponentsLimit (WebIDL dictionary member) §: Defined in Protected Audience
GenerateBidOutput.adCost (WebIDL dictionary member) §: Defined in Protected Audience
ReportWinBrowserSignals.adCost (WebIDL dictionary member) §: Defined in Protected Audience
add (concept for AbortSignal ) §: Defined in DOM; Referenced in Fetch, HTML, Streams, Web Bluetooth, Translator and Language Detector APIs, Writing Assistance APIs, Direct Sockets API, EyeDropper API, Idle Detection API, Observable, Prioritized Task Scheduling, Web Serial API, Protected Audience, Web Smart Card API, Web Platform Design Principles, Geolocation Sensor, Web Locks API, WebRTC Encoded Transform, WebTransport
add (CSS value for mask-composite ) §: Defined in CSS Masking 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Animations 2
"add" (value for CompositeOperation, CompositeOperationOrAuto enumeration WebIDL enumerations) §: Defined in Web Animations
add (algorithm for usage scope ) §: Defined in WebGPU
"add" (value for GPUBlendOperation WebIDL enumeration) §: Defined in WebGPU
MLOpSupportLimits.add (WebIDL dictionary member) §: Defined in Web Neural Network API
add a CSS style sheet (concept) §: Defined in CSSOM
add a range header (concept for request ) §: Defined in Fetch; Referenced in HTML, Background Fetch
add a track (algorithm for MediaStream ) §: Defined in Media Capture and Streams
add an element to the top layer (concept) §: Defined in CSS Positioned Layout 4; Referenced in Fullscreen API, HTML
add an event listener (concept) §: Defined in DOM; Referenced in HTML, Captured Surface Control, Observable, CSSOM View
add lifetime promise (concept for ExtendableEvent ) §: Defined in Service Workers
add mock camera (concept for extension commands ) §: Defined in Media Capture Automation
add mock microphone (concept for extension commands ) §: Defined in Media Capture Automation
add the debug header (concept) §: Defined in Device Bound Session Credentials
add two types (concept for CSSNumericValue ) §: Defined in CSS Typed OM 1; Referenced in CSS Values 4
DOMTokenList.add(...tokens) (WebIDL operation) §: Defined in DOM
CSSNumericValue.add(...values) (WebIDL operation) §: Defined in CSS Typed OM 1
DataTransferItemList.add() (WebIDL operation) §: Defined in HTML
RdfDataset.add() (WebIDL operation) §: Defined in JSON-LD 1.1 Processing Algorithms and API
RdfGraph.add() (WebIDL operation) §: Defined in JSON-LD 1.1 Processing Algorithms and API
MLGraphBuilder.add(a, b, options) (WebIDL operation) §: Defined in Web Neural Network API
ContentIndex.add(description) (WebIDL operation) §: Defined in Content Index
HTMLOptionsCollection.add(element, before) (WebIDL operation) §: Defined in HTML
HTMLSelectElement.add(element, before) (WebIDL operation) §: Defined in HTML
FontFaceSet.add(font) (WebIDL operation) §: Defined in CSS Font Loading 3
Cache.add(request) (WebIDL operation) §: Defined in Service Workers
Atomics.add(typedArray, index, value) (WebIDL operation) §: Defined in ECMAScript
IDBObjectStore.add(value, key) (WebIDL operation) §: Defined in Indexed DB 3.0
add(value) (WebIDL operation for Set ) §: Defined in ECMAScript
WeakSet.add(value) (WebIDL operation) §: Defined in ECMAScript
Cache.addAll(requests) (WebIDL operation) §: Defined in Service Workers
CanvasGradient.addColorStop(offset, color) (WebIDL operation) §: Defined in HTML
TextTrack.addCue(cue) (WebIDL operation) §: Defined in HTML; Referenced in WebVTT: The Web Video Text Tracks Format
XRInputSourcesChangeEvent.added (WebIDL attribute) §: Defined in WebXR Device API
XRInputSourcesChangeEventInit.added (WebIDL dictionary member) §: Defined in WebXR Device API
MutationRecord.addedNodes (WebIDL attribute) §: Defined in DOM
BufferedChangeEvent.addedRanges (WebIDL attribute) §: Defined in Media Source Extensions™
BufferedChangeEventInit.addedRanges (WebIDL dictionary member) §: Defined in Media Source Extensions™
AddEntriesFromIterable (algorithm) §: Defined in ECMAScript
EventTarget.addEventListener(type, callback, options) (WebIDL operation) §: Defined in DOM; Referenced in HTML, CSSOM View, Web Platform Design Principles, UI Events
AddEventListenerOptions (WebIDL dictionary) §: Defined in DOM; Related terms: AddEventListenerOptions.once, AddEventListenerOptions.passive, AddEventListenerOptions.signal; see also WebIDLPedia
SpeechGrammarList.addFromString(string, weight) (WebIDL operation) §: Defined in Web Speech API
SpeechGrammarList.addFromURI(src, weight) (WebIDL operation) §: Defined in Web Speech API
RTCPeerConnection.addIceCandidate!overload-1() (WebIDL operation) §: Defined in WebRTC 1.0
RTCPeerConnection.addIceCandidate() (WebIDL operation) §: Defined in WebRTC 1.0
additional capability deserialization algorithm (concept) §: Defined in WebDriver; Referenced in WebDriver BiDi
additional-name (value for autocomplete attribute of button element, autocomplete attribute of fieldset element, autocomplete attribute of input element, autocomplete attribute of object element, autocomplete attribute of output element, autocomplete attribute of select element, autocomplete attribute of textarea element ) §: Defined in HTML
AuctionAdInterestGroup.additionalBidKey (WebIDL dictionary member) §: Defined in Protected Audience
AuctionAdConfig.additionalBids (WebIDL dictionary member) §: Defined in Protected Audience
AeadParams.additionalData (WebIDL dictionary member) §: Defined in Modern Algorithms in the Web Cryptography API
AesGcmParams.additionalData (WebIDL dictionary member) §: Defined in Web Cryptography 2
PaymentDetailsModifier.additionalDisplayItems (WebIDL dictionary member) §: Defined in Payment Request API
additive (markup attribute for animate ) §: Defined in SVG Animations 2; Referenced in SVG 2
additive (CSS value for system descriptor of @counter-style @rule ) §: Defined in CSS Counter Styles 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
additive (CSS value for environment-blending descriptor of @media @rule ) §: Defined in Media Queries 5
"additive" (value for XREnvironmentBlendMode WebIDL enumeration) §: Defined in WebXR Augmented Reality 1
additive color space (concept) §: Defined in CSS Color 4
additive tuple (concept) §: Defined in CSS Counter Styles 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
additive-symbols (CSS descriptor for @counter-style ) §: Defined in CSS Counter Styles 3
CSSCounterStyleRule.additiveSymbols (WebIDL attribute) §: Defined in CSS Counter Styles 3
MediaQueryList.addListener(callback) (WebIDL operation) §: Defined in CSSOM View
Worklet.addModule(moduleURL, options) (WebIDL operation) §: Defined in HTML; Referenced in Shared Storage API, Web Audio API, Web Audio API 1.1
Path2D.addPath(path, transform) (WebIDL operation) §: Defined in HTML
HandwritingStroke.addPoint(point) (WebIDL operation) §: Defined in Handwriting Recognition API
Selection.addRange() (WebIDL operation) §: Defined in Selection API
RTCIceTransport.addRemoteCandidate() (WebIDL operation) §: Defined in IceTransport Extensions for WebRTC
address (markup element) §: Defined in HTML; Referenced in HTML Accessibility API Mappings 1.0, ARIA in HTML, WebDriver
"address" (value for ContactProperty WebIDL enumeration) §: Defined in Contact Picker API
ContactInfo.address (WebIDL dictionary member) §: Defined in Contact Picker API
MemoryDescriptor.address (WebIDL dictionary member) §
MemoryDescriptor.address (WebIDL dictionary member) §
MemoryDescriptor.address (WebIDL dictionary member) §
MemoryDescriptor.address (WebIDL dictionary member) §: Defined in WebAssembly JavaScript Interface: Content Security Policy , WebAssembly JavaScript Interface: ESM Integration , WebAssembly JavaScript Interface: JS String Builtins , WebAssembly JavaScript Interface
RTCIceCandidate.address (WebIDL attribute) §: Defined in WebRTC 1.0
RTCIceCandidateStats.address (WebIDL dictionary member) §: Defined in WebRTC Statistics
RTCPeerConnectionIceErrorEvent.address (WebIDL attribute) §: Defined in WebRTC 1.0
RTCPeerConnectionIceErrorEventInit.address (WebIDL dictionary member) §: Defined in WebRTC 1.0
TableDescriptor.address (WebIDL dictionary member) §
TableDescriptor.address (WebIDL dictionary member) §
TableDescriptor.address (WebIDL dictionary member) §
TableDescriptor.address (WebIDL dictionary member) §: Defined in WebAssembly JavaScript Interface: Content Security Policy , WebAssembly JavaScript Interface: ESM Integration , WebAssembly JavaScript Interface: JS String Builtins , WebAssembly JavaScript Interface
address line (concept for physical address ) §: Defined in Contact Picker API
address-level1 (value for autocomplete attribute of button element, autocomplete attribute of fieldset element, autocomplete attribute of input element, autocomplete attribute of object element, autocomplete attribute of output element, autocomplete attribute of select element, autocomplete attribute of textarea element ) §: Defined in HTML
address-level2 (value for autocomplete attribute of button element, autocomplete attribute of fieldset element, autocomplete attribute of input element, autocomplete attribute of object element, autocomplete attribute of output element, autocomplete attribute of select element, autocomplete attribute of textarea element ) §: Defined in HTML
address-level3 (value for autocomplete attribute of button element, autocomplete attribute of fieldset element, autocomplete attribute of input element, autocomplete attribute of object element, autocomplete attribute of output element, autocomplete attribute of select element, autocomplete attribute of textarea element ) §: Defined in HTML
address-level4 (value for autocomplete attribute of button element, autocomplete attribute of fieldset element, autocomplete attribute of input element, autocomplete attribute of object element, autocomplete attribute of output element, autocomplete attribute of select element, autocomplete attribute of textarea element ) §: Defined in HTML
address-line1 (value for autocomplete attribute of button element, autocomplete attribute of fieldset element, autocomplete attribute of input element, autocomplete attribute of object element, autocomplete attribute of output element, autocomplete attribute of select element, autocomplete attribute of textarea element ) §: Defined in HTML
address-line2 (value for autocomplete attribute of button element, autocomplete attribute of fieldset element, autocomplete attribute of input element, autocomplete attribute of object element, autocomplete attribute of output element, autocomplete attribute of select element, autocomplete attribute of textarea element ) §: Defined in HTML
address-line3 (value for autocomplete attribute of button element, autocomplete attribute of fieldset element, autocomplete attribute of input element, autocomplete attribute of object element, autocomplete attribute of output element, autocomplete attribute of select element, autocomplete attribute of textarea element ) §: Defined in HTML
addressable character (concept) §: Defined in SVG 2
AddressErrors (WebIDL dictionary) §: Defined in Payment Request API; Related terms: AddressErrors.addressLine, AddressErrors.city, AddressErrors.country, AddressErrors.dependentLocality, AddressErrors.organization, AddressErrors.phone, AddressErrors.postalCode, AddressErrors.recipient, AddressErrors.region, AddressErrors.sortingCode; see also WebIDLPedia
AddressErrors.addressLine (WebIDL dictionary member) §: Defined in Payment Request API
ContactAddress.addressLine (WebIDL attribute) §: Defined in Contact Picker API
GPUSamplerDescriptor.addressModeU (WebIDL dictionary member) §: Defined in WebGPU
GPUSamplerDescriptor.addressModeV (WebIDL dictionary member) §: Defined in WebGPU
GPUSamplerDescriptor.addressModeW (WebIDL dictionary member) §: Defined in WebGPU
AddressType (WebIDL enumeration) §: Defined in WebAssembly JavaScript Interface: Content Security Policy , WebAssembly JavaScript Interface: ESM Integration , WebAssembly JavaScript Interface: JS String Builtins , WebAssembly JavaScript Interface; Related terms: value i32, value i64; see also WebIDLPedia
AddressValue (WebIDL type alias) §: Defined in WebAssembly JavaScript Interface: Content Security Policy , WebAssembly JavaScript Interface: ESM Integration , WebAssembly JavaScript Interface: JS String Builtins , WebAssembly JavaScript Interface; see also WebIDLPedia
AddRestrictedFunctionProperties (algorithm) §: Defined in ECMAScript
InstallEvent.addRoutes(rules) (WebIDL operation) §: Defined in Service Workers
CSSStyleSheet.addRule(selector, style, index) (WebIDL operation) §: Defined in CSSOM
External.AddSearchProvider() (WebIDL operation) §: Defined in HTML
addsourcebuffer (event) §: Defined in Media Source Extensions™
MediaSource.addSourceBuffer() (WebIDL operation) §: Defined in Media Source Extensions™
HandwritingDrawing.addStroke(stroke) (WebIDL operation) §: Defined in Handwriting Recognition API
Subscriber.addTeardown(teardown) (WebIDL operation) §: Defined in Observable
HTMLMediaElement.addTextTrack(kind, label, language) (WebIDL operation) §: Defined in HTML; Referenced in Open Screen Application Protocol
AddToKeptObjects (algorithm) §: Defined in ECMAScript
addtrack (event for AudioTrackList, TextTrackList interface, VideoTrackList interface ) §: Defined in HTML; Referenced in Media Source Extensions™
addtrack (event) §: Defined in Media Capture and Streams; Referenced in Media Capture from DOM Elements
MediaStream.addTrack() (WebIDL operation) §: Defined in Media Capture and Streams
RTCPeerConnection.addTrack() (WebIDL operation) §: Defined in WebRTC 1.0
addTransceiver sendEncodings validation steps (concept for RTCPeerConnection ) §: Defined in WebRTC 1.0
RTCPeerConnection.addTransceiver() (WebIDL operation) §: Defined in WebRTC 1.0
AddValueToKeyedGroup (algorithm) §: Defined in ECMAScript
AddWaiter (algorithm) §: Defined in ECMAScript
adopt (concept) §: Defined in DOM; Referenced in HTML
Adopted Draft (concept) §: Defined in W3C Process Document
DocumentOrShadowRoot.adoptedStyleSheets (WebIDL attribute) §: Defined in CSSOM
adopting steps (concept) §: Defined in DOM; Referenced in HTML, Portals
Document.adoptNode(node) (WebIDL operation) §: Defined in DOM
PortalActivateEvent.adoptPredecessor() (WebIDL operation) §: Defined in Portals
AdRender (WebIDL dictionary) §: Defined in Protected Audience; Related terms: AdRender.height, AdRender.url, AdRender.width; see also WebIDLPedia
AuctionAd.adRenderId (WebIDL dictionary member) §: Defined in Protected Audience
GenerateBidInterestGroup.ads (WebIDL dictionary member) §: Defined in Protected Audience
GenerateBidInterestGroup.adSizes (WebIDL dictionary member) §: Defined in Protected Audience
"adts" (value for AacBitstreamFormat WebIDL enumeration) §: Defined in AAC WebCodecs Registration
advance measure (concept for <length> ) §: Defined in CSS Values 3 , CSS Values 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
IDBCursor.advance(count) (WebIDL operation) §: Defined in Indexed DB 3.0
Constraints.advanced (WebIDL dictionary member) §: Defined in Media Capture and Streams
MediaTrackConstraints.advanced (WebIDL dictionary member) §: Defined in Media Capture and Streams
FontMetrics.advances (WebIDL attribute) §: Defined in Font Metrics API 1
AdvanceStringIndex (algorithm) §: Defined in ECMAScript
advertisementreceived (event for BluetoothDeviceEventHandlers ) §: Defined in Web Bluetooth; Referenced in Web Bluetooth Scanning
Advisory Board (concept) §: Defined in W3C Process Document
Advisory Committee (concept) §: Defined in W3C Process Document
Advisory Committee Appeal (concept) §: Defined in W3C Process Document
Advisory Committee representative (concept) §: Defined in W3C Process Document; Referenced in W3C Patent Policy
Advisory Committee review (concept) §: Defined in W3C Process Document
AeadParams (WebIDL dictionary) §: Defined in Modern Algorithms in the Web Cryptography API; Related terms: AeadParams.additionalData, AeadParams.iv, AeadParams.tagLength; see also WebIDLPedia
"AES_128_CTR_HMAC_SHA256_32" (value for SFrameCipherSuite WebIDL enumeration) §: Defined in WebRTC Encoded Transform
"AES_128_CTR_HMAC_SHA256_64" (value for SFrameCipherSuite WebIDL enumeration) §: Defined in WebRTC Encoded Transform
"AES_128_CTR_HMAC_SHA256_80" (value for SFrameCipherSuite WebIDL enumeration) §: Defined in WebRTC Encoded Transform
"AES_128_GCM_SHA256_128" (value for SFrameCipherSuite WebIDL enumeration) §: Defined in WebRTC Encoded Transform
"AES_256_GCM_SHA512_128" (value for SFrameCipherSuite WebIDL enumeration) §: Defined in WebRTC Encoded Transform
AesCbcParams (WebIDL dictionary) §: Defined in Web Cryptography 2; Related terms: AesCbcParams.iv; see also WebIDLPedia
AesCtrParams (WebIDL dictionary) §: Defined in Web Cryptography 2; Related terms: AesCtrParams.counter, AesCtrParams.length; see also WebIDLPedia
AesDerivedKeyParams (WebIDL dictionary) §: Defined in Web Cryptography 2; Related terms: AesDerivedKeyParams.length; see also WebIDLPedia
AesGcmParams (WebIDL dictionary) §: Defined in Web Cryptography 2; Related terms: AesGcmParams.additionalData, AesGcmParams.iv, AesGcmParams.tagLength; see also WebIDLPedia
AesKeyAlgorithm (WebIDL dictionary) §: Defined in Web Cryptography 2; Related terms: AesKeyAlgorithm.length; see also WebIDLPedia
AesKeyGenParams (WebIDL dictionary) §: Defined in Web Cryptography 2; Related terms: AesKeyGenParams.length; see also WebIDLPedia
::after (CSS selector) §: Defined in CSS Pseudo-Elements 4 , CSS 2 , Selectors 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Snapshot 2025, CSS Cascading 3, CSS Cascading 4, CSS Cascading 5, CSS Containment 1, CSS Containment 2, CSS Generated Content 3, CSS Display 3, CSS Display 4, CSS Form Control Styling 1, CSS Layout API 1, CSS Lists 3, CSS Nesting, CSS Overflow 5, CSS Paged Media 3, CSS Pseudo-Elements 4, CSS Scroll Snap 1, CSS Speech 1, CSS User Interface 4, CSSOM, Selectors 4, WebVTT: The Web Video Text Tracks Format
after (concept for boundary point ) §: Defined in DOM; Referenced in execCommand, URL Fragment Text Directives, Selection API
after (CSS value for content() ) §: Defined in CSS Generated Content 3
after (CSS value for scroll-marker-group ) §: Defined in CSS Overflow 5
after phase (concept for animation effect ) §: Defined in Web Animations; Referenced in CSS Animations 2, Web Animations 2
after-change style (concept) §: Defined in CSS Transitions; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Transitions 2, CSS Values 5, Web Animations
"after-transition" (value for NavigationFocusReset WebIDL enumeration) §: Defined in HTML
"after-transition" (value for NavigationScrollBehavior WebIDL enumeration) §: Defined in HTML
AnimationEffect.after(...effects) (WebIDL operation) §: Defined in Web Animations 2
ChildNode.after(...nodes) (WebIDL operation) §: Defined in DOM
afterprint (event for Window ) §: Defined in HTML
<age> (CSS type for voice-family ) §: Defined in CSS Speech 1
agent (concept for realm ) §: Defined in HTML; Referenced in WebAssembly JavaScript Interface: Exception Handling, Prioritized Task Scheduling, Protected Audience
agent (concept for ECMAScript ) §: Defined in ECMAScript; Referenced in ECMAScript® 2026 Internationalization API, Time Zone Canonicalization, WebAssembly JavaScript Interface: Content Security Policy, WebAssembly JavaScript Interface: ESM Integration, WebAssembly JavaScript Interface: Promise Integration, WebAssembly JavaScript Interface: JS String Builtins, Protected Audience, Compute Pressure 1, Media Source Extensions™, Service Workers, WebAssembly JavaScript Interface, WebGPU
agent cluster (concept for ECMAScript ) §: Defined in ECMAScript; Referenced in HTML, WebAssembly JavaScript Interface: Content Security Policy, WebAssembly JavaScript Interface: ESM Integration, WebAssembly JavaScript Interface: Exception Handling, WebAssembly JavaScript Interface: Promise Integration, WebAssembly JavaScript Interface: JS String Builtins, Web IDL, Document-Isolation-Policy, Measure Memory API, Protected Audience, Media Source Extensions™, WebAssembly JavaScript Interface, WebGPU
Agent Events Record (concept for ECMAScript ) §: Defined in ECMAScript
Agent Record (concept for ECMAScript ) §: Defined in ECMAScript
agent signifier (concept for ECMAScript ) §: Defined in ECMAScript; Referenced in HTML, Measure Memory API
agent-order slice (concept for ECMAScript ) §: Defined in ECMAScript
AgentCanSuspend (algorithm) §: Defined in ECMAScript
AgentSignifier (algorithm) §: Defined in ECMAScript
AggregateError (exception) §: Defined in ECMAScript; Related terms: AggregateError.message, AggregateError.name, new AggregateError(errors, message, options)
%AggregateError.prototype% (WebIDL interface) §: Defined in ECMAScript; Referenced in ECMAScript Async Explicit Resource Management, ECMAScript Explicit Resource Management; see also WebIDLPedia
new AggregateError(errors, message, options) (WebIDL constructor) §: Defined in ECMAScript
%AggregateError% (exception) §: Defined in ECMAScript; Referenced in ECMAScript Async Explicit Resource Management, ECMAScript Explicit Resource Management, Source Phase Imports
aggregation coordinator (concept) §: Defined in Private Aggregation API; Referenced in Shared Storage API
ProtectedAudiencePrivateAggregationConfig.aggregationCoordinatorOrigin (WebIDL dictionary member) §: Defined in Protected Audience
SharedStoragePrivateAggregationConfig.aggregationCoordinatorOrigin (WebIDL dictionary member) §: Defined in Shared Storage API
AttributionConversionOptions.aggregationService (WebIDL dictionary member) §: Defined in Privacy-Preserving Attribution 1
Attribution.aggregationServices (WebIDL attribute) §: Defined in Privacy-Preserving Attribution 1
AI task source (concept) §: Defined in Writing Assistance APIs; Referenced in Translator and Language Detector APIs
MediaMetadata.album (WebIDL attribute) §: Defined in Media Session
MediaMetadataInit.album (WebIDL dictionary member) §: Defined in Media Session
alert (WebIDL attribute for unhandled-prompt-behavior-alert ) §: Defined in WebDriver BiDi
Window.alert() (WebIDL operation) §: Defined in HTML; Referenced in Web Platform Design Principles
Window.alert(message) (WebIDL operation) §: Defined in HTML; Referenced in WebDriver BiDi, WebDriver
JsonWebKey.alg (WebIDL dictionary member) §: Defined in Web Cryptography 2
PublicKeyCredentialParameters.alg (WebIDL dictionary member) §: Defined in Web Authentication; Referenced in Secure Payment Confirmation
Algorithm (WebIDL dictionary) §: Defined in Web Cryptography 2; Related terms: Algorithm.name; see also WebIDLPedia
CryptoKey.algorithm (WebIDL attribute) §: Defined in Web Cryptography 2
RTCDtlsFingerprint.algorithm (WebIDL dictionary member) §: Defined in WebRTC 1.0
WebTransportHash.algorithm (WebIDL dictionary member) §: Defined in WebTransport
algorithm for determining the form of an embellished operator (algorithm) §: Defined in MathML Core
algorithm for determining the properties of an embellished operator (algorithm) §: Defined in MathML Core
algorithm for stretching operators along the block axis (algorithm) §: Defined in MathML Core
algorithm for stretching operators along the inline axis (algorithm) §: Defined in MathML Core
algorithm to determine the category of an operator (algorithm) §: Defined in MathML Core
algorithm to set the properties of an operator from its category (algorithm) §: Defined in MathML Core
AlgorithmIdentifier (WebIDL type alias) §: Defined in Web Cryptography 2; see also WebIDLPedia
alias (CSS value for cursor ) §: Defined in CSS User Interface 3 , CSS User Interface 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
aliceblue (concept) §: Defined in CSS Color 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
aliceblue (CSS value for <color>, <named-color> type ) §: Defined in CSS Color 4
align (markup attribute for caption ) §: Defined in HTML
align (markup attribute for col ) §: Defined in HTML
align (markup attribute for div ) §: Defined in HTML
align (markup attribute for embed ) §: Defined in HTML
align (markup attribute for hr ) §: Defined in HTML
align (markup attribute for h1, h2 element, h3 element, h4 element, h5 element, h6 element ) §: Defined in HTML
align (markup attribute for iframe ) §: Defined in HTML
align (markup attribute for input ) §: Defined in HTML
align (markup attribute for img ) §: Defined in HTML
align (markup attribute for legend ) §: Defined in HTML
align (markup attribute for object ) §: Defined in HTML
align (markup attribute for p ) §: Defined in HTML
align (markup attribute for table ) §: Defined in HTML
align (markup attribute for tbody ) §: Defined in HTML
align (markup attribute for td, th element ) §: Defined in HTML
align (markup attribute for tr ) §: Defined in HTML
HTMLDivElement.align (WebIDL attribute) §: Defined in HTML
HTMLEmbedElement.align (WebIDL attribute) §: Defined in HTML
HTMLHeadingElement.align (WebIDL attribute) §: Defined in HTML
HTMLHRElement.align (WebIDL attribute) §: Defined in HTML
HTMLIFrameElement.align (WebIDL attribute) §: Defined in HTML
HTMLImageElement.align (WebIDL attribute) §: Defined in HTML
HTMLInputElement.align (WebIDL attribute) §: Defined in HTML
HTMLLegendElement.align (WebIDL attribute) §: Defined in HTML
HTMLObjectElement.align (WebIDL attribute) §: Defined in HTML
HTMLParagraphElement.align (WebIDL attribute) §: Defined in HTML
HTMLTableCaptionElement.align (WebIDL attribute) §: Defined in HTML
HTMLTableCellElement.align (WebIDL attribute) §: Defined in HTML
HTMLTableColElement.align (WebIDL attribute) §: Defined in HTML
HTMLTableElement.align (WebIDL attribute) §: Defined in HTML
HTMLTableRowElement.align (WebIDL attribute) §: Defined in HTML
HTMLTableSectionElement.align (WebIDL attribute) §: Defined in HTML
SVGPreserveAspectRatio.align (WebIDL attribute) §: Defined in SVG 2
VTTCue.align (WebIDL attribute) §: Defined in WebVTT: The Web Video Text Tracks Format
align-content (CSS property) §: Defined in CSS Box Alignment 3 , CSS Flexbox 1; Referenced in Compatibility, CSS Snapshot 2022, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2024, CSS Snapshot 2025, CSS Snapshot 2025, CSS Display 3, CSS Display 4, CSS Grid Layout 3, CSS Inline Layout 3, CSS Rhythmic Sizing, CSS Typed OM 1; Related terms: CSS value baseline, CSS value center, CSS value center, CSS value end, CSS value first baseline, CSS value flex-end, CSS value flex-end, CSS value flex-start, CSS value flex-start, CSS value last baseline, CSS value normal, CSS value space-around, CSS value space-around, CSS value space-between, CSS value space-between, CSS value space-evenly, CSS value start, CSS value stretch, CSS value stretch
align-items (CSS property) §: Defined in CSS Box Alignment 3 , CSS Flexbox 1; Referenced in Compatibility, CSS Snapshot 2022, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2024, CSS Snapshot 2025, CSS Snapshot 2025, CSS Anchor Positioning, CSS Typed OM 1; Related terms: CSS value anchor-center, CSS value auto, CSS value baseline, CSS value baseline, CSS value center, CSS value dialog, CSS value first baseline, CSS value flex-end, CSS value flex-start, CSS value last baseline, CSS value stretch
align-self (CSS property) §: Defined in CSS Box Alignment 3 , CSS Flexbox 1; Referenced in Compatibility, CSS Snapshot 2022, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2024, CSS Snapshot 2025, CSS Snapshot 2025, CSS Anchor Positioning, CSS Rhythmic Sizing, CSS Typed OM 1; Related terms: CSS value anchor-center, CSS value auto, CSS value auto, CSS value baseline, CSS value baseline, CSS value center, CSS value center, CSS value dialog, CSS value end, CSS value first baseline, CSS value flex-end, CSS value flex-end, CSS value flex-start, CSS value flex-start, CSS value last baseline, CSS value normal, CSS value self-end, CSS value self-start, CSS value start, CSS value stretch, CSS value stretch
CSSPositionTryDescriptors.align-self (WebIDL attribute) §: Defined in CSS Anchor Positioning
alignment baseline (concept) §: Defined in CSS Box Alignment 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Flexbox 1, CSS Grid Layout 3
alignment baseline (concept) §: Defined in CSS Inline Layout 3
alignment baseline (concept) §: Defined in SVG 2
alignment character (CSS value for text-align ) §: Defined in CSS Text 4
alignment container (concept) §: Defined in CSS Box Alignment 3; Referenced in CSS Backgrounds 4, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Positioned Layout 3, CSS Scroll Snap 1, CSS Values 5
alignment subject (concept) §: Defined in CSS Box Alignment 3; Referenced in CSS Backgrounds 4, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Grid Layout 3, CSS Overflow 3, CSS Positioned Layout 3, CSS Scroll Snap 1, CSS Values 5
alignment-baseline (CSS property) §: Defined in CSS Inline Layout 3; Referenced in CSS Box Alignment 3, CSS Masking 1, CSS Typed OM 1; Related terms: CSS value alphabetic, CSS value baseline, CSS value central, CSS value ideographic, CSS value mathematical, CSS value middle, CSS value text-after-edge, CSS value text-before-edge, CSS value text-bottom, CSS value text-top
CSSPositionTryDescriptors.alignSelf (WebIDL attribute) §: Defined in CSS Anchor Positioning
AlignSetting (WebIDL enumeration) §: Defined in WebVTT: The Web Video Text Tracks Format; Related terms: value center, value end, value left, value right, value start; see also WebIDLPedia
alink (markup attribute for body ) §: Defined in HTML
HTMLBodyElement.aLink (WebIDL attribute) §: Defined in HTML
Document.alinkColor (WebIDL attribute) §: Defined in HTML
"all" (value for SameSiteCookiesType WebIDL enumeration) §: Defined in Extending Storage Access API to non-cookie storage
all (CSS value for anchor-scope ) §: Defined in CSS Anchor Positioning
all (CSS value for border-limit ) §: Defined in CSS Borders and Box Decorations 4
all (CSS value for break-after, break-before property ) §: Defined in CSS Fragmentation 4
all (CSS property) §: Defined in CSS Cascading 3 , CSS Cascading 4 , CSS Cascading 5; Referenced in CSS Variables 2, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Cascading 6, CSS Logical Properties 1, CSS Spatial Navigation 1, CSS Transitions, CSS Typed OM 1, CSS User Interface 4, CSS Variables 1; Related terms: CSS value inherit, CSS value initial, CSS value revert, CSS value revert-layer, CSS value revert-rule, CSS value unset
all (CSS value for initial-letter-wrap ) §: Defined in CSS Inline Layout 3
all (CSS value for column-span ) §: Defined in CSS Multicol 1 , CSS Multicol 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
"all" (value for FocusableAreaSearchMode WebIDL enumeration) §: Defined in CSS Spatial Navigation 1
all (CSS value for clear ) §: Defined in CSS Page Floats
all (CSS value for text-decoration-skip-box ) §: Defined in CSS Text Decoration 4
all (CSS value for text-decoration-skip-spaces ) §: Defined in CSS Text Decoration 4
all (CSS value for text-decoration-skip-ink ) §: Defined in CSS Text Decoration 4
all (CSS value for transition-property ) §: Defined in CSS Transitions; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Transitions 2
all (CSS value for user-select ) §: Defined in CSS User Interface 4
all (CSS value for text-combine-upright ) §: Defined in CSS Writing Modes 3 , CSS Writing Modes 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
all (CSS value for @media ) §: Defined in CSS 2 , Media Queries 4 , Media Queries 5; Referenced in CSS Snapshot 2022, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Snapshot 2025, CSS Cascading 4, CSS Speech 1
"all" (value for ScrollIntoViewContainer WebIDL enumeration) §: Defined in CSSOM View
"all" (value for EchoCancellationModeEnum WebIDL enumeration) §: Defined in Media Capture and Streams
all (CSS value for timeline-scope ) §: Defined in Scroll-driven Animations
"all" (value for ServiceWorkerUpdateViaCache WebIDL enumeration) §: Defined in Service Workers
"all" (value for ClientType WebIDL enumeration) §: Defined in Service Workers
"all" (value for GPUTextureAspect WebIDL enumeration) §: Defined in WebGPU
"all" (value for RTCIceTransportPolicy WebIDL enumeration) §: Defined in WebRTC 1.0
Document.all (WebIDL attribute) §: Defined in HTML; Referenced in ECMAScript
StorageAccessTypes.all (WebIDL dictionary member) §: Defined in Extending Storage Access API to non-cookie storage
GPUColorWrite.ALL (WebIDL constant) §: Defined in WebGPU
"all-petite-caps" (value for CanvasFontVariantCaps WebIDL enumeration) §: Defined in HTML
all-petite-caps (CSS value for font-variant-caps ) §: Defined in CSS Fonts 4; Referenced in CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
all-scroll (CSS value for cursor ) §: Defined in CSS User Interface 3 , CSS User Interface 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
"all-small-caps" (value for CanvasFontVariantCaps WebIDL enumeration) §: Defined in HTML
all-small-caps (CSS value for font-variant-caps ) §: Defined in CSS Fonts 4; Referenced in CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
Promise.all(iterable) (WebIDL operation) §: Defined in ECMAScript; Referenced in Web IDL
AllAcceptedCredentialsOptions.allAcceptedCredentialIds (WebIDL dictionary member) §: Defined in Web Authentication
AllAcceptedCredentialsOptions (WebIDL dictionary) §: Defined in Web Authentication; Related terms: AllAcceptedCredentialsOptions.allAcceptedCredentialIds, AllAcceptedCredentialsOptions.rpId, AllAcceptedCredentialsOptions.userId; see also WebIDLPedia
AllCharacters (algorithm) §: Defined in ECMAScript
AllImportAttributesSupported (algorithm) §: Defined in ECMAScript; Referenced in Deferred Imports Evaluation
AllocateArrayBuffer (algorithm) §: Defined in ECMAScript; Referenced in Web IDL
AllocateSharedArrayBuffer (algorithm) §: Defined in ECMAScript; Referenced in Web IDL
AllocateTypedArray (algorithm) §: Defined in ECMAScript; Referenced in Uint8Array to/from base64
AllocateTypedArrayBuffer (algorithm) §: Defined in ECMAScript
AudioData.allocationSize(options) (WebIDL operation) §: Defined in WebCodecs
VideoFrame.allocationSize(options) (WebIDL operation) §: Defined in WebCodecs
'allow' (grammar) §: Defined in Content Security Policy 3
allow (markup attribute for iframe ) §: Defined in HTML; Referenced in Fullscreen API, Fenced Frame, WebOTP API, Generic Sensor API, Geolocation, HTML Accessibility API Mappings 1.0, Payment Request API, Permissions Policy, Permissions, Web Share API, Web Authentication
allow (markup attribute for fencedframe ) §: Defined in Fenced Frame
HTMLFencedFrameElement.allow (WebIDL attribute) §: Defined in Fenced Frame
HTMLIFrameElement.allow (WebIDL attribute) §: Defined in HTML; Referenced in Capability Delegation
allow declarative shadow roots (concept for Document ) §: Defined in DOM; Referenced in HTML Sanitizer API
allow focus steps (concept) §: Defined in HTML
Allow-Cross-Origin-Event-Reporting: (HTTP header) §: Defined in Fenced Frame
Allow-CSP-From: (HTTP header) §: Defined in Content Security Policy: Embedded Enforcement
allow-downloads (value for sandbox attribute of iframe element ) §: Defined in HTML; Referenced in Fenced Frame
allow-end (CSS value for hanging-punctuation ) §: Defined in CSS Text 3 , CSS Text 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
Allow-Fenced-Frame-Automatic-Beacons: (HTTP header) §: Defined in Fenced Frame
allow-forms (value for sandbox attribute of iframe element ) §: Defined in HTML; Referenced in Fenced Frame
allow-keywords (CSS value for interpolate-size ) §: Defined in CSS Values 5
allow-modals (value for sandbox attribute of iframe element ) §: Defined in HTML; Referenced in Fenced Frame
allow-orientation-lock (value for sandbox attribute of iframe element ) §: Defined in HTML; Referenced in Fenced Frame
allow-pointer-lock (value for sandbox attribute of iframe element ) §: Defined in HTML; Referenced in Fenced Frame
allow-popups (value for sandbox attribute of iframe element ) §: Defined in HTML; Referenced in Fenced Frame
allow-popups-to-escape-sandbox (value for sandbox attribute of iframe element ) §: Defined in HTML; Referenced in Fenced Frame
allow-presentation (value for sandbox attribute of iframe element ) §: Defined in HTML; Referenced in Fenced Frame
allow-same-origin (value for sandbox attribute of iframe element ) §: Defined in HTML; Referenced in Fenced Frame
allow-scripts (value for sandbox attribute of iframe element ) §: Defined in HTML; Referenced in Fenced Frame
allow-storage-access-by-user-activation (value for sandbox attribute of iframe element ) §: Defined in The Storage Access API
allow-top-navigation (value for sandbox attribute of iframe element ) §: Defined in HTML; Referenced in Fenced Frame
allow-top-navigation-by-user-activation (value for sandbox attribute of iframe element ) §: Defined in HTML; Referenced in Fenced Frame
allow-top-navigation-to-custom-protocols (value for sandbox attribute of iframe element ) §: Defined in HTML; Referenced in Fenced Frame
PermissionsPolicyViolationReportBody.allowAttribute (WebIDL attribute) §: Defined in Permissions Policy
Sanitizer.allowAttribute(attribute) (WebIDL operation) §: Defined in HTML Sanitizer API
GenerateBidOutput.allowComponentAuction (WebIDL dictionary member) §: Defined in Protected Audience
ScoreAdOutput.allowComponentAuction (WebIDL dictionary member) §: Defined in Protected Audience
PublicKeyCredentialRequestOptions.allowCredentials (WebIDL dictionary member) §: Defined in Web Authentication; Referenced in Secure Payment Confirmation
PublicKeyCredentialRequestOptionsJSON.allowCredentials (WebIDL dictionary member) §: Defined in Web Authentication
"allowed" (value for AutoplayPolicy WebIDL enumeration) §: Defined in Autoplay Policy Detection
allowed reporting origins (concept for fenced frame reporting metadata ) §: Defined in Fenced Frame; Referenced in Protected Audience
allowed required constraints for device selection (concept) §: Defined in Media Capture and Streams
Allowed signed exchange link info (concept) §: Defined in Loading Signed Exchanges
allowed to modify the clipboard (concept) §: Defined in Clipboard API and events
allowed to use (concept) §: Defined in HTML; Referenced in Fetch, Fullscreen API, Private Aggregation API, Topics API, The Storage Access API, Web Bluetooth, Web Bluetooth Scanning, Writing Assistance APIs, Attribution Reporting, Capability Delegation, Digital Goods API, Direct Sockets API, Fenced Frame, Idle Detection API, Keyboard Map, Local Font Access API, Prerendering Revamped, Page Lifecycle, Facilitated Payment Link Type in HTML, Web Serial API, Shared Storage API, Protected Audience, User-Agent Client Hints, WebOTP API, Web Smart Card API, WebHID API, WebUSB API, Audio Output Devices API, Battery Status API, Compute Pressure 1, Credential Management 1, Encrypted Media Extensions, Federated Credential Management API, Gamepad, Generic Sensor API, Geolocation, Media Capture and Streams, Viewport Capture, Device Orientation and Motion, Payment Request API, Permissions, Picture-in-Picture, Privacy-Preserving Attribution 1, Screen Capture, Screen Wake Lock API, Web Share API, Web Authentication, Web MIDI API, Web Neural Network API, Window Management
allowed to use (concept for PrivateAggregation ) §: Defined in Private Aggregation API; Referenced in Protected Audience
allowed-alt-sxg (value for rel attribute of link element ) §: Defined in Loading Signed Exchanges
"allowed-muted" (value for AutoplayPolicy WebIDL enumeration) §: Defined in Autoplay Policy Detection
AllowedBluetoothDevice (WebIDL dictionary) §: Defined in Web Bluetooth; Related terms: AllowedBluetoothDevice.[[device]], AllowedBluetoothDevice.allowedManufacturerData, AllowedBluetoothDevice.allowedServices, AllowedBluetoothDevice.deviceId, AllowedBluetoothDevice.mayUseGATT; see also WebIDLPedia
SerialPortRequestOptions.allowedBluetoothServiceClassIds (WebIDL dictionary member) §: Defined in Web Serial API
BluetoothPermissionStorage.allowedDevices (WebIDL dictionary member) §: Defined in Web Bluetooth
USBPermissionStorage.allowedDevices (WebIDL dictionary member) §: Defined in WebUSB API
PermissionsPolicy.allowedFeatures() (WebIDL operation) §: Defined in Permissions Policy
BluetoothDevice.[[allowedManufacturerData]] (internal slot) §: Defined in Web Bluetooth
AllowedBluetoothDevice.allowedManufacturerData (WebIDL dictionary member) §: Defined in Web Bluetooth
AuctionAd.allowedReportingOrigins (WebIDL dictionary member) §: Defined in Protected Audience
BluetoothDevice.[[allowedServices]] (internal slot) §: Defined in Web Bluetooth
AllowedBluetoothDevice.allowedServices (WebIDL dictionary member) §: Defined in Web Bluetooth
AllowedUSBDevice (WebIDL dictionary) §: Defined in WebUSB API; Related terms: AllowedUSBDevice.[[devices]], AllowedUSBDevice.productId, AllowedUSBDevice.serialNumber, AllowedUSBDevice.vendorId; see also WebIDLPedia
Sanitizer.allowElement(element) (WebIDL operation) §: Defined in HTML Sanitizer API
HTMLIFrameElement.allowFullscreen (WebIDL attribute) §: Defined in HTML
allowfullscreen (markup attribute for iframe ) §: Defined in HTML; Referenced in Fullscreen API, HTML Accessibility API Mappings 1.0, Permissions Policy
allowlist (concept) §: Defined in Permissions Policy; Referenced in Fenced Frame
WebTransportOptions.allowPooling (WebIDL dictionary member) §: Defined in WebTransport
AllowResizable (WebIDL extended attribute) §: Defined in Web IDL
allows all inline behavior (concept for source list ) §: Defined in Content Security Policy 3; Referenced in Content Security Policy: Embedded Enforcement
PermissionsPolicy.allowsFeature(feature, origin) (WebIDL operation) §: Defined in Permissions Policy
AllowShared (WebIDL extended attribute) §: Defined in Web IDL; Referenced in Encoding, WebGPU
AllowSharedBufferSource (WebIDL type alias) §: Defined in Web IDL; Referenced in Encoding, File System, WebCodecs, WebGPU, Web Neural Network API; see also WebIDLPedia
allowtransparency (markup attribute for iframe ) §: Defined in HTML
ClipboardPermissionDescriptor.allowWithoutGesture (WebIDL dictionary member) §: Defined in Clipboard API and events
"allpass" (value for BiquadFilterType WebIDL enumeration) §: Defined in Web Audio API , Web Audio API 1.1
Promise.allSettled(iterable) (WebIDL operation) §: Defined in ECMAScript
AuctionAdConfig.allSlotsRequestedSizes (WebIDL dictionary member) §: Defined in Protected Audience
alpha (markup attribute for input ) §: Defined in HTML
alpha (CSS value for rgb() ) §: Defined in CSS Color 5
alpha (CSS value for hsl() ) §: Defined in CSS Color 5
alpha (CSS value for hwb() ) §: Defined in CSS Color 5
alpha (CSS value for lab() ) §: Defined in CSS Color 5
alpha (CSS value for oklab() ) §: Defined in CSS Color 5
alpha (CSS value for lch() ) §: Defined in CSS Color 5
alpha (CSS value for oklch() ) §: Defined in CSS Color 5
alpha (CSS value for alpha() ) §: Defined in CSS Color 5
alpha (CSS value for color() ) §: Defined in CSS Color 5
alpha (CSS value for ictcp() ) §: Defined in CSS Color HDR 1
alpha (CSS value for jzazbz() ) §: Defined in CSS Color HDR 1
alpha (CSS value for jzczhz() ) §: Defined in CSS Color HDR 1
alpha (CSS value for mask-mode ) §: Defined in CSS Masking 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
alpha (CSS value for mask-border-mode ) §: Defined in CSS Masking 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
alpha (CSS value for mask-type ) §: Defined in CSS Masking 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
CanvasRenderingContext2DSettings.alpha (WebIDL dictionary member) §: Defined in HTML
CSSColor.alpha (WebIDL attribute) §: Defined in CSS Typed OM 1
CSSHSL.alpha (WebIDL attribute) §: Defined in CSS Typed OM 1
CSSHWB.alpha (WebIDL attribute) §: Defined in CSS Typed OM 1
CSSLab.alpha (WebIDL attribute) §: Defined in CSS Typed OM 1
CSSLCH.alpha (WebIDL attribute) §: Defined in CSS Typed OM 1
CSSOKLab.alpha (WebIDL attribute) §: Defined in CSS Typed OM 1
CSSOKLCH.alpha (WebIDL attribute) §: Defined in CSS Typed OM 1
CSSRGB.alpha (WebIDL attribute) §: Defined in CSS Typed OM 1
DeviceMotionEventRotationRate.alpha (WebIDL attribute) §: Defined in Device Orientation and Motion
DeviceMotionEventRotationRateInit.alpha (WebIDL dictionary member) §: Defined in Device Orientation and Motion
DeviceOrientationEvent.alpha (WebIDL attribute) §: Defined in Device Orientation and Motion
DeviceOrientationEventInit.alpha (WebIDL dictionary member) §: Defined in Device Orientation and Motion
GPUBlendState.alpha (WebIDL dictionary member) §: Defined in WebGPU
HTMLInputElement.alpha (WebIDL attribute) §: Defined in HTML
ImageBitmapRenderingContextSettings.alpha (WebIDL dictionary member) §: Defined in HTML
MLEluOptions.alpha (WebIDL dictionary member) §: Defined in Web Neural Network API
MLGemmOptions.alpha (WebIDL dictionary member) §: Defined in Web Neural Network API
MLHardSigmoidOptions.alpha (WebIDL dictionary member) §: Defined in Web Neural Network API
MLLeakyReluOptions.alpha (WebIDL dictionary member) §: Defined in Web Neural Network API
MLLinearOptions.alpha (WebIDL dictionary member) §: Defined in Web Neural Network API
PaintRenderingContext2DSettings.alpha (WebIDL dictionary member) §: Defined in CSS Painting API 1
VideoEncoderConfig.alpha (WebIDL dictionary member) §: Defined in WebCodecs
VideoFrameInit.alpha (WebIDL dictionary member) §: Defined in WebCodecs
XRWebGLLayerInit.alpha (WebIDL dictionary member) §: Defined in WebXR Device API
GPUColorWrite.ALPHA (WebIDL constant) §: Defined in WebGPU
alpha channel (concept) §: Defined in CSS Color 4; Referenced in Largest Contentful Paint
"alpha-blend" (value for XREnvironmentBlendMode WebIDL enumeration) §: Defined in WebXR Augmented Reality 1
<alpha-value> (CSS type for <color> ) §: Defined in CSS Color 4; Referenced in CSS Color 5, CSS Color HDR 1, CSSOM
alpha() (CSS function) §: Defined in CSS Color 5; Referenced in CSS Color HDR 1; Related terms: CSS value alpha
Alphabet (concept) §: Defined in Internationalization Glossary
"alphabetic" (value for CanvasTextBaseline WebIDL enumeration) §: Defined in HTML
alphabetic (CSS value for system descriptor of @counter-style @rule ) §: Defined in CSS Counter Styles 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
alphabetic (CSS value for dominant-baseline ) §: Defined in CSS Inline Layout 3
alphabetic (CSS value for alignment-baseline, vertical-align property ) §: Defined in CSS Inline Layout 3
alphabetic (CSS value for <<text-edge>>, line-fit-edge property ) §: Defined in CSS Inline Layout 3
alphabetic (CSS value for initial-letter-align ) §: Defined in CSS Inline Layout 3
alphabetic baseline (concept) §: Defined in CSS Inline Layout 3
TextMetrics.alphabeticBaseline (WebIDL attribute) §: Defined in HTML
GPUCanvasConfiguration.alphaMode (WebIDL dictionary member) §: Defined in WebGPU
AlphaOption (WebIDL enumeration) §: Defined in WebCodecs; Related terms: value discard, value keep; see also WebIDLPedia
EncodedVideoChunkMetadata.alphaSideData (WebIDL dictionary member) §: Defined in WebCodecs
GPUMultisampleState.alphaToCoverageEnabled (WebIDL dictionary member) §: Defined in WebGPU
<alphavalue> (concept) §: Defined in CSS Color 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
ALPN negotiated protocol (concept for connection timing info ) §: Defined in Fetch; Referenced in Resource Timing, WebDriver BiDi
already triggered external error (concept) §: Defined in Private Aggregation API
alt (markup attribute for img ) §: Defined in HTML; Referenced in HTML Accessibility API Mappings 1.0, ARIA in HTML
alt (markup attribute for area ) §: Defined in HTML; Referenced in HTML Accessibility API Mappings 1.0
alt (markup attribute for input ) §: Defined in HTML; Referenced in HTML Accessibility API Mappings 1.0
HTMLAreaElement.alt (WebIDL attribute) §: Defined in HTML
HTMLImageElement.alt (WebIDL attribute) §: Defined in HTML
HTMLInputElement.alt (WebIDL attribute) §: Defined in HTML
alternate (value for rel attribute of a, rel attribute of area element, rel attribute of link element ) §: Defined in HTML; Referenced in Loading Signed Exchanges
alternate (CSS value for animation-direction ) §: Defined in CSS Animations 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
alternate (CSS value for ruby-position ) §: Defined in CSS Ruby Annotation Layout 1; Referenced in HTML Ruby Markup Extensions
"alternate" (value for PlaybackDirection WebIDL enumeration) §: Defined in Web Animations
"alternate" (value for AnimationTriggerBehavior WebIDL enumeration) §: Defined in Web Animations 2
USBInterface.alternate (WebIDL attribute) §: Defined in WebUSB API
alternate AC representative (concept) §: Defined in W3C Process Document
Alternate signed exchange link info (concept) §: Defined in Loading Signed Exchanges
Alternate signed exchange preload info (concept) §: Defined in Loading Signed Exchanges
alternate-reverse (CSS value for animation-direction ) §: Defined in CSS Animations 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
"alternate-reverse" (value for PlaybackDirection WebIDL enumeration) §: Defined in Web Animations
USBEndpoint.[[alternateInterface]] (internal slot) §: Defined in WebUSB API
USBInterface.[[alternates]] (internal slot) §
USBInterface.[[alternates]] (internal slot) §: Defined in WebUSB API , WebUSB API
USBAlternateInterface.[[alternateSetting]] (internal slot) §
USBAlternateInterface.[[alternateSetting]] (internal slot) §: Defined in WebUSB API , WebUSB API
HandwritingHints.alternatives (WebIDL dictionary member) §: Defined in Handwriting Recognition API
HandwritingHintsQueryResult.alternatives (WebIDL dictionary member) §: Defined in Handwriting Recognition API
altitude (WebIDL attribute for geolocation override ) §: Defined in WebDriver BiDi
GeolocationCoordinates.altitude (WebIDL attribute) §: Defined in Geolocation
GeolocationSensor.altitude (WebIDL attribute) §: Defined in Geolocation Sensor
GeolocationSensorReading.altitude (WebIDL dictionary member) §: Defined in Geolocation Sensor
altitudeAccuracy (WebIDL attribute for geolocation override ) §: Defined in WebDriver BiDi
GeolocationCoordinates.altitudeAccuracy (WebIDL attribute) §: Defined in Geolocation
GeolocationSensor.altitudeAccuracy (WebIDL attribute) §: Defined in Geolocation Sensor
GeolocationSensorReading.altitudeAccuracy (WebIDL dictionary member) §: Defined in Geolocation Sensor
PointerEvent.altitudeAngle (WebIDL attribute) §
PointerEvent.altitudeAngle (WebIDL attribute) §: Defined in Pointer Events , Pointer Events
PointerEventInit.altitudeAngle (WebIDL dictionary member) §
PointerEventInit.altitudeAngle (WebIDL dictionary member) §: Defined in Pointer Events , Pointer Events
Touch.altitudeAngle (WebIDL attribute) §: Defined in Touch Events
TouchInit.altitudeAngle (WebIDL dictionary member) §: Defined in Touch Events
EventModifierInit.altKey (WebIDL dictionary member) §: Defined in UI Events
KeyboardEvent.altKey (WebIDL attribute) §: Defined in UI Events
MouseEvent.altKey (WebIDL attribute) §: Defined in UI Events
TouchEvent.altKey (WebIDL attribute) §: Defined in Touch Events
alttext (markup attribute for math ) §: Defined in MathML Core
"@always" (value for JsonLdEmbed WebIDL enumeration) §: Defined in JSON-LD 1.1 Framing
always (CSS value for position-visibility ) §: Defined in CSS Anchor Positioning
always (CSS value for break-after, break-before property ) §: Defined in CSS Fragmentation 4; Referenced in CSS Regions 1
always (CSS value for scrollbar-gutter ) §: Defined in CSS Overflow 4
always (CSS value for scroll-snap-stop ) §: Defined in CSS Scroll Snap 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
always (CSS value for speak ) §: Defined in CSS Speech 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Display 3, CSS Display 4
always (CSS value for hyphenate-limit-lines ) §: Defined in CSS Text 4
always (CSS value for page-break-after, page-break-before property, page-break-inside property ) §: Defined in CSS 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2025
"always" (value for RedEyeReduction WebIDL enumeration) §: Defined in MediaStream Image Capture
"always" (value for CursorCaptureConstraint WebIDL enumeration) §: Defined in Screen Capture
"always" (value for GPUCompareFunction WebIDL enumeration) §: Defined in WebGPU
"ambient" (value for AudioSessionType WebIDL enumeration) §: Defined in Audio Session
"ambient-light-sensor" (permission name) §: Defined in Ambient Light Sensor
AmbientLightSensor (WebIDL interface) §: Defined in Ambient Light Sensor; Related terms: AmbientLightSensor.illuminance, new AmbientLightSensor(sensorOptions); see also WebIDLPedia
new AmbientLightSensor(sensorOptions) (WebIDL constructor) §: Defined in Ambient Light Sensor
ambiguous image URL (concept for CSS ) §: Defined in CSS Images 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
PaymentItem.amount (WebIDL dictionary member) §: Defined in Payment Request API
PaymentShippingOption.amount (WebIDL dictionary member) §: Defined in Payment Request API
amount to debit (concept for exfiltration budget metadata ) §: Defined in Fenced Frame
amount to debit reference (concept for exfiltration budget metadata reference ) §: Defined in Fenced Frame
amplitude (markup attribute for feComponentTransfer ) §: Defined in Filter Effects 1
SVGComponentTransferFunctionElement.amplitude (WebIDL attribute) §: Defined in Filter Effects 1
an iframe srcdoc document (concept) §: Defined in HTML; Referenced in Content Security Policy 3
An+B (concept) §: Defined in CSS Syntax 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
<an+b> (CSS type) §: Defined in CSS Syntax 3; Referenced in CSS GCPM 3, Selectors 4
analogous components (concept) §: Defined in CSS Color 4; Referenced in CSS Color 5
AnalyserNode (WebIDL interface) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefinedfftSize, undefinedfrequencyBinCount, undefinedmaxDecibels, undefinedminDecibels, undefinedsmoothingTimeConstant, undefinedAnalyserNode(context, options), undefinedgetByteFrequencyData(array), undefinedgetByteTimeDomainData(array), undefinedgetFloatFrequencyData(array), undefinedgetFloatTimeDomainData(array); see also WebIDLPedia
new AnalyserNode(context, options) (WebIDL constructor) §
new AnalyserNode(context, options) (WebIDL constructor) §: Defined in Web Audio API , Web Audio API 1.1
AnalyserOptions (WebIDL dictionary) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefinedfftSize, undefinedmaxDecibels, undefinedminDecibels, undefinedsmoothingTimeConstant; see also WebIDLPedia
ancestor (concept for tree ) §: Defined in DOM; Referenced in HTML, execCommand, Fenced Frame, CSS View Transitions 2, Pointer Lock 2.0, UI Events, WebXR Device API
"ancestor" (value for ScriptWindowAttribution WebIDL enumeration) §: Defined in Long Animation Frames API
ancestor navigables (concept for Document ) §: Defined in HTML; Referenced in Fetch, Long Animation Frames API, Fenced Frame, Long Tasks API, Mixed Content
ancestor-source (grammar) §: Defined in Content Security Policy 3
ancestor-source-list (grammar) §: Defined in Content Security Policy 3
Location.ancestorOrigins (WebIDL attribute) §: Defined in HTML
WindowClient.ancestorOrigins (WebIDL attribute) §: Defined in Service Workers
anchor functions (concept) §: Defined in CSS Anchor Positioning
anchor node (concept for scroll-anchoring ) §: Defined in CSS Scroll Anchoring 1
Anchor positioning (concept) §: Defined in CSS Anchor Positioning; Referenced in CSS Anchor Positioning 2
anchor priority candidate (concept) §: Defined in CSS Scroll Anchoring 1; Referenced in CSS Overflow 5
anchor reference (concept) §: Defined in CSS Anchor Positioning
anchor-center (CSS value for align-items, align-self property, justify-items property, justify-self property ) §: Defined in CSS Anchor Positioning
<anchor-name> (CSS value for position-anchor ) §: Defined in CSS Anchor Positioning
<anchor-name> (CSS type) §: Defined in CSS Anchor Positioning
anchor-name (CSS property) §: Defined in CSS Anchor Positioning; Referenced in CSS Scoping 1; Related terms: CSS value <dashed-ident>#, CSS value none
anchor-scope (CSS property) §: Defined in CSS Anchor Positioning; Referenced in CSS Animations 2, CSS Scoping 1; Related terms: CSS value all, CSS value none
<anchor-side> (CSS type) §: Defined in CSS Anchor Positioning
<anchor-size> (CSS type) §: Defined in CSS Anchor Positioning
anchor-size() (CSS function) §: Defined in CSS Anchor Positioning; Related terms: CSS value block, CSS value height, CSS value inline, CSS value self-block, CSS value self-inline, CSS value width
anchor() (CSS function) §: Defined in CSS Anchor Positioning; Referenced in CSS Values 4; Related terms: CSS value bottom, CSS value center, CSS value end, CSS value inside, CSS value left, CSS value outside, CSS value right, CSS value self-end, CSS value self-start, CSS value start, CSS value top
String.anchor(name) (WebIDL operation) §: Defined in ECMAScript
anchored (CSS value for container-type ) §: Defined in CSS Anchor Positioning 2
<anchored-in-parens> (CSS type) §: Defined in CSS Anchor Positioning 2
<anchored-query> (CSS type) §: Defined in CSS Anchor Positioning 2
Selection.anchorNode (WebIDL attribute) §: Defined in Selection API
Selection.anchorOffset (WebIDL attribute) §: Defined in Selection API
Document.anchors (WebIDL attribute) §: Defined in HTML
anchors-valid (CSS value for position-visibility ) §: Defined in CSS Anchor Positioning
anchors-visible (CSS value for position-visibility ) §: Defined in CSS Anchor Positioning
XRAnchor.anchorSpace (WebIDL attribute) §: Defined in WebXR Anchors
Atomics.and(typedArray, index, value) (WebIDL operation) §: Defined in ECMAScript
<angle> (CSS value for image-orientation ) §: Defined in CSS Images 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
<angle> (CSS type) §: Defined in CSS Values 3 , CSS Values 4; Referenced in CSS Conditional Values 1, CSS Color 4, CSS Color 5, CSS Fonts 4, CSS Images 3, CSS Images 4, CSS Properties and Values API 1, CSS Shapes 1, CSS Transforms 1, CSS Transforms 2, CSS Typed OM 1, CSS Writing Modes 3, CSS Writing Modes 4, CSSOM, Filter Effects 1; Related terms: CSS value deg, CSS value grad, CSS value rad, CSS value turn
"angle" (value for CSSNumericBaseType WebIDL enumeration) §: Defined in CSS Typed OM 1
CSSNumericType.angle (WebIDL dictionary member) §: Defined in CSS Typed OM 1
CSSRotate.angle (WebIDL attribute) §: Defined in CSS Typed OM 1
ScreenOrientation.angle (WebIDL attribute) §: Defined in Screen Orientation
SVGTransform.angle (WebIDL attribute) §: Defined in SVG 2
<angle-percentage> (CSS type) §: Defined in CSS Values 3 , CSS Values 4; Referenced in CSS Images 4, CSS Typed OM 1
<angular-color-hint> (CSS type) §: Defined in CSS Images 4
<angular-color-stop> (CSS type) §: Defined in CSS Images 4
<angular-color-stop-list> (CSS type) §: Defined in CSS Images 4
GamepadPose.angularAcceleration (WebIDL attribute) §: Defined in Gamepad Extensions
GamepadPose.angularVelocity (WebIDL attribute) §: Defined in Gamepad Extensions
XRPose.angularVelocity (WebIDL attribute) §: Defined in WebXR Device API
Animatable (WebIDL interface) §: Defined in Web Animations; Referenced in Web Animations 2; Related terms: undefinedanimate(keyframes, options), undefinedgetAnimations(options); see also WebIDLPedia
animate (markup element) §: Defined in SVG Animations 2; Referenced in CSS Masking 1, CSS Transforms 1, CSS Transforms 2, Filter Effects 1; Related terms: markup attribute accumulate, markup attribute additive, markup attribute attributeName, markup attribute begin, markup attribute dur, markup attribute end, markup attribute fill, markup attribute from, markup attribute href, markup attribute keyPoints, markup attribute keySplines, markup attribute keyTimes, markup attribute max, markup attribute min, markup attribute onbegin, markup attribute onend, markup attribute onrepeat, markup attribute origin, markup attribute repeatCount, markup attribute repeatDur, markup attribute requiredExtensions, markup attribute restart, markup attribute rotate, markup attribute systemLanguage, markup attribute values
Animatable.animate(keyframes, options) (WebIDL operation) §
Animatable.animate(keyframes, options) (WebIDL operation) §: Defined in Web Animations , Web Animations 2; Referenced in Pointer-driven Animations, Scroll-driven Animations
<animateable-feature> (CSS type) §: Defined in CSS Will Change 1
ImageTrack.[[animated]] (internal slot) §
ImageTrack.[[animated]] (internal slot) §: Defined in WebCodecs , WebCodecs
animated image document (concept) §: Defined in SVG Integration
SVGUseElement.animatedInstanceRoot (WebIDL attribute) §: Defined in SVG 2
SVGAnimatedPoints.animatedPoints (WebIDL attribute) §: Defined in SVG 2
animateMotion (markup element) §: Defined in SVG Animations 2; Referenced in CSS Masking 1
animateTransform (markup element) §: Defined in SVG Animations 2; Referenced in CSS Masking 1, Filter Effects 1
animation (CSS property) §: Defined in CSS Animations 1; Referenced in Compatibility, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Animations 2, CSS Color 4, CSS Typed OM 1, CSS Values 3, CSS Values 4, Scroll-driven Animations
animation (concept) §: Defined in Web Animations; Referenced in Pointer-driven Animations, CSS Anchor Positioning, CSS Animations 2, CSS Transitions 2, Scroll-driven Animations; Related terms: concept associated effect, concept current time, concept document for timing, concept hold time, concept play state, concept relevant, concept reset an animation’s pending tasks, concept set the associated effect of an animation, concept set the current time, concept set the timeline of an animation, concept silently set the current time, concept start time
Animation (WebIDL interface) §: Defined in Web Animations; Referenced in Pointer-driven Animations, CSS Animation Worklet API, CSS Animations 2, CSS Transitions 2, Scroll-driven Animations, Web Animations 2; Related terms: undefinedcurrentTime, Animation.effect, Animation.finished, Animation.id, Animation.oncancel, Animation.onfinish, Animation.onremove, Animation.overallProgress, Animation.pending, Animation.playbackRate, Animation.playState, Animation.rangeEnd, Animation.rangeStart, Animation.ready, Animation.replaceState, undefinedstartTime, Animation.timeline, Animation.trigger, new Animation(effect, timeline), Animation.cancel(), Animation.commitStyles(), Animation.finish(), Animation.pause(), Animation.persist(), Animation.play(), Animation.reverse(), Animation.updatePlaybackRate(playbackRate); see also WebIDLPedia
animation attachment range (concept) §: Defined in Scroll-driven Animations; Referenced in Pointer-driven Animations, Web Animations 2
animation composite order (concept) §: Defined in Web Animations
animation frame (concept) §: Defined in Web Animations; Referenced in CSS Animations 2, CSS Transitions 2
Animation Origin (concept) §: Defined in CSS Cascading 3 , CSS Cascading 4 , CSS Cascading 5; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Anchor Positioning, Web Animations
animation trigger (concept) §: Defined in Web Animations 2
animation trigger behavior (concept) §: Defined in Web Animations 2
animation trigger state (concept) §: Defined in Web Animations 2
Animation type (concept) §: Defined in Web Animations; Referenced in CSS Containment 2, CSS Display 4, CSS Masking 1, CSS Transitions, CSS Transitions 2
<animation-action> (CSS type) §: Defined in CSS Animations 2; Related terms: CSS value none, CSS value pause, CSS value play, CSS value play-backwards, CSS value play-forwards, CSS value replay, CSS value reset
animation-composition (CSS property) §: Defined in CSS Animations 2; Referenced in CSS Typed OM 1
animation-delay (CSS property) §: Defined in CSS Animations 1; Referenced in Compatibility, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Animations 2, Scroll-driven Animations
animation-direction (CSS property) §: Defined in CSS Animations 1; Referenced in Compatibility, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Animations 2; Related terms: CSS value alternate, CSS value alternate-reverse, CSS value normal, CSS value reverse
animation-duration (CSS property) §: Defined in CSS Animations 1 , CSS Animations 2; Referenced in Compatibility, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025; Related terms: CSS value auto
animation-fill-mode (CSS property) §: Defined in CSS Animations 1; Referenced in Compatibility, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Animations 2, Web Animations; Related terms: CSS value backwards, CSS value both, CSS value forwards, CSS value none
animation-iteration-count (CSS property) §: Defined in CSS Animations 1; Referenced in Compatibility, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Animations 2, CSS Values 4, Scroll-driven Animations; Related terms: CSS value infinite
animation-name (CSS property) §: Defined in CSS Animations 1; Referenced in Compatibility, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Animations 2, CSS Scoping 1, CSS Values 3, CSS Values 4, Scroll-driven Animations, Web Animations; Related terms: CSS value <keyframes-name>, CSS value none
animation-play-state (CSS property) §: Defined in CSS Animations 1; Referenced in Compatibility, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Animations 2; Related terms: CSS value paused, CSS value running
animation-range (CSS property) §: Defined in Scroll-driven Animations; Referenced in CSS Animations 2
animation-range-center (CSS property) §: Defined in Pointer-driven Animations; Related terms: CSS value <timeline-range-name> <length-percentage>?, CSS value normal
animation-range-end (CSS property) §: Defined in Scroll-driven Animations; Referenced in CSS Animations 2, Web Animations 2; Related terms: CSS value <timeline-range-name> <length-percentage>?, CSS value normal
animation-range-start (CSS property) §: Defined in Scroll-driven Animations; Referenced in CSS Animations 2, Web Animations 2; Related terms: CSS value <timeline-range-name> <length-percentage>?, CSS value normal
animation-timeline (CSS property) §: Defined in CSS Animations 2; Referenced in Pointer-driven Animations, CSS Values 5, Scroll-driven Animations; Related terms: CSS value auto, CSS value none
animation-timing-function (CSS property) §: Defined in CSS Animations 1; Referenced in Compatibility, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Animations 2, CSS Syntax 3, CSS Values 3, CSS Values 4, CSS Values 5
animation-trigger (CSS property) §: Defined in CSS Animations 2; Related terms: CSS value [ <dashed-ident> <animation-action>+ ]+, CSS value none
new Animation(effect, timeline) (WebIDL constructor) §: Defined in Web Animations; Referenced in Web Animations 2
animationcancel (event for GlobalEventHandlers ) §: Defined in CSS Animations 1; Referenced in CSS Animations 2
AnimationEffect (WebIDL interface) §: Defined in Web Animations; Referenced in CSS Animation Worklet API, CSS Animations 2, Web Animations 2; Related terms: AnimationEffect.nextSibling, AnimationEffect.parent, AnimationEffect.previousSibling, AnimationEffect.after(...effects), AnimationEffect.before(...effects), undefinedgetComputedTiming(), AnimationEffect.getTiming(), AnimationEffect.remove(), AnimationEffect.replace(...effects), AnimationEffect.updateTiming(timing); see also WebIDLPedia
animationend (event for GlobalEventHandlers ) §: Defined in CSS Animations 1; Referenced in CSS Animations 2
AnimationEvent (WebIDL interface) §: Defined in CSS Animations 1; Referenced in CSS Animations 2; Related terms: AnimationEvent.animationName, AnimationEvent.elapsedTime, AnimationEvent.pseudoElement, new AnimationEvent(type, animationEventInitDict); see also WebIDLPedia
new AnimationEvent(type, animationEventInitDict) (WebIDL constructor) §: Defined in CSS Animations 1
AnimationEventInit (WebIDL dictionary) §: Defined in CSS Animations 1; Related terms: AnimationEventInit.animationName, AnimationEventInit.elapsedTime, AnimationEventInit.pseudoElement; see also WebIDLPedia
AnimationFrameProvider (WebIDL interface) §: Defined in HTML; Referenced in HTMLVideoElement.requestVideoFrameCallback(); Related terms: AnimationFrameProvider.cancelAnimationFrame(handle), AnimationFrameProvider.requestAnimationFrame(callback); see also WebIDLPedia
animationiteration (event for GlobalEventHandlers ) §: Defined in CSS Animations 1; Referenced in CSS Animations 2
AnimationEvent.animationName (WebIDL attribute) §: Defined in CSS Animations 1
AnimationEventInit.animationName (WebIDL dictionary member) §: Defined in CSS Animations 1
CSSAnimation.animationName (WebIDL attribute) §: Defined in CSS Animations 2
AnimationNodeList (WebIDL interface) §: Defined in Web Animations 2; Related terms: AnimationNodeList.length, AnimationNodeList.item(index); see also WebIDLPedia
AnimationPlaybackEvent (WebIDL interface) §: Defined in Web Animations , Web Animations 2; Related terms: undefinedcurrentTime, undefinedtimelineTime, undefinedAnimationPlaybackEvent(type, eventInitDict); see also WebIDLPedia
new AnimationPlaybackEvent(type, eventInitDict) (WebIDL constructor) §
new AnimationPlaybackEvent(type, eventInitDict) (WebIDL constructor) §: Defined in Web Animations , Web Animations 2
AnimationPlaybackEventInit (WebIDL dictionary) §: Defined in Web Animations , Web Animations 2; Related terms: undefinedcurrentTime, undefinedtimelineTime; see also WebIDLPedia
AnimationPlayState (WebIDL enumeration) §: Defined in Web Animations; Related terms: value finished, value idle, value paused, value running; see also WebIDLPedia
AnimationReplaceState (WebIDL enumeration) §: Defined in Web Animations; Related terms: value active, value persisted, value removed; see also WebIDLPedia
animationstart (event for GlobalEventHandlers ) §: Defined in CSS Animations 1; Referenced in CSS Animations 2
AnimationTimeline (WebIDL interface) §: Defined in Web Animations; Referenced in Pointer-driven Animations, CSS Animation Worklet API, Scroll-driven Animations, Web Animations 2; Related terms: undefinedcurrentTime, AnimationTimeline.duration, AnimationTimeline.play(effect); see also WebIDLPedia
AnimationTrigger (WebIDL interface) §: Defined in Web Animations 2; Related terms: AnimationTrigger.behavior, AnimationTrigger.exitRangeEnd, AnimationTrigger.exitRangeStart, AnimationTrigger.rangeEnd, AnimationTrigger.rangeStart, AnimationTrigger.timeline, new AnimationTrigger(options); see also WebIDLPedia
new AnimationTrigger(options) (WebIDL constructor) §: Defined in Web Animations 2
AnimationTriggerBehavior (WebIDL enumeration) §: Defined in Web Animations 2; Related terms: value alternate, value once, value repeat, value state; see also WebIDLPedia
AnimationTriggerOptions (WebIDL dictionary) §: Defined in Web Animations 2; Related terms: AnimationTriggerOptions.behavior, AnimationTriggerOptions.exitRangeEnd, AnimationTriggerOptions.exitRangeStart, AnimationTriggerOptions.rangeEnd, AnimationTriggerOptions.rangeStart, AnimationTriggerOptions.timeline; see also WebIDLPedia
animationWorklet (WebIDL attribute for CSS ) §: Defined in CSS Animation Worklet API
AnimationWorkletGlobalScope (WebIDL interface) §: Defined in CSS Animation Worklet API; Related terms: AnimationWorkletGlobalScope.registerAnimator(name, animatorCtor); see also WebIDLPedia
AnimatorInstanceConstructor (WebIDL callback) §: Defined in CSS Animation Worklet API
WorkletAnimation.animatorName (WebIDL attribute) §: Defined in CSS Animation Worklet API
SVGAnimatedAngle.animVal (WebIDL attribute) §: Defined in SVG 2
SVGAnimatedBoolean.animVal (WebIDL attribute) §: Defined in SVG 2
SVGAnimatedEnumeration.animVal (WebIDL attribute) §: Defined in SVG 2
SVGAnimatedInteger.animVal (WebIDL attribute) §: Defined in SVG 2
SVGAnimatedLength.animVal (WebIDL attribute) §: Defined in SVG 2
SVGAnimatedLengthList.animVal (WebIDL attribute) §: Defined in SVG 2
SVGAnimatedNumber.animVal (WebIDL attribute) §: Defined in SVG 2
SVGAnimatedNumberList.animVal (WebIDL attribute) §: Defined in SVG 2
SVGAnimatedPreserveAspectRatio.animVal (WebIDL attribute) §: Defined in SVG 2; Referenced in CSS Transforms 1
SVGAnimatedRect.animVal (WebIDL attribute) §: Defined in SVG 2
SVGAnimatedString.animVal (WebIDL attribute) §: Defined in SVG 2
SVGAnimatedTransformList.animVal (WebIDL attribute) §: Defined in SVG 2
"annexb" (value for AvcBitstreamFormat WebIDL enumeration) §: Defined in H.264
"annexb" (value for HevcBitstreamFormat WebIDL enumeration) §: Defined in H.265
annotated types (concept) §: Defined in Web IDL; Related terms: concept inner type
@annotation (CSS @rule for @font-feature-values ) §: Defined in CSS Fonts 4; Referenced in CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
annotation (markup element) §: Defined in MathML Core; Related terms: markup attribute encoding
CSSFontFeatureValuesRule.annotation (WebIDL attribute) §: Defined in CSS Fonts 4
annotation pairing (concept) §: Defined in HTML Ruby Markup Extensions
annotation-xml (markup element) §: Defined in MathML Core; Referenced in HTML; Related terms: markup attribute encoding
annotation(<feature-value-name>) (CSS value for font-variant-alternates ) §: Defined in CSS Fonts 4; Referenced in CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
announce the rtcdatachannel as open (algorithm) §: Defined in WebRTC 1.0
Announcing a data channel as closed (algorithm) §: Defined in WebRTC 1.0
anonymization policy (concept for prefetch record ) §: Defined in Prefetch; Referenced in HTML, Prerendering Revamped
anonymous (value for crossorigin attribute of audio element, crossorigin attribute of img element, crossorigin attribute of link element, crossorigin attribute of script, crossorigin attribute of video element ) §: Defined in HTML
anonymous (concept for CSS ) §: Defined in CSS Display 3 , CSS Display 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Flexbox 1, CSS Inline Layout 3, CSS Layout API 1, CSS Lists 3, CSS Multicol 1, CSS Multicol 2, CSS Table 3, CSS Text Decoration 3, CSS Text Decoration 4, CSSOM View
anonymous (CSS value for <request-url-modifier> ) §: Defined in CSS Values 5
"answer" (value for RTCSdpType WebIDL enumeration) §: Defined in WebRTC 1.0
SmartCardConnectionStatus.answerToReset (WebIDL dictionary member) §: Defined in Web Smart Card API
SmartCardReaderStateOut.answerToReset (WebIDL dictionary member) §: Defined in Web Smart Card API
<antecedent> (CSS type) §: Defined in CSS Conditional Values 1
XRWebGLLayer.antialias (WebIDL attribute) §: Defined in WebXR Device API
XRWebGLLayerInit.antialias (WebIDL dictionary member) §: Defined in WebXR Device API
WebTransport.[[AnticipatedConcurrentIncomingBidirectionalStreams]] (internal slot) §: Defined in WebTransport
WebTransport.anticipatedConcurrentIncomingBidirectionalStreams (WebIDL attribute) §: Defined in WebTransport
WebTransportOptions.anticipatedConcurrentIncomingBidirectionalStreams (WebIDL dictionary member) §: Defined in WebTransport
WebTransport.[[AnticipatedConcurrentIncomingUnidirectionalStreams]] (internal slot) §: Defined in WebTransport
WebTransport.anticipatedConcurrentIncomingUnidirectionalStreams (WebIDL attribute) §: Defined in WebTransport
WebTransportOptions.anticipatedConcurrentIncomingUnidirectionalStreams (WebIDL dictionary member) §: Defined in WebTransport
DeprecationReportBody.anticipatedRemoval (WebIDL attribute) §: Defined in Deprecation Reporting
antiquewhite (concept) §: Defined in CSS Color 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
antiquewhite (CSS value for <color>, <named-color> type ) §: Defined in CSS Color 4
any (CSS value for <position-area-query> ) §: Defined in CSS Anchor Positioning 2
any (value for closedby attribute of dialog element ) §: Defined in HTML
any (WebIDL interface) §: Defined in Web IDL; Referenced in Console, DOM, Fetch, Notifications API, Private Aggregation API, Streams, Web NFC, WebAssembly JavaScript Interface: Content Security Policy, WebAssembly JavaScript Interface: ESM Integration, WebAssembly JavaScript Interface: Exception Handling, WebAssembly JavaScript Interface: Promise Integration, WebAssembly JavaScript Interface: JS String Builtins, WebAssembly JavaScript Interface: Type Reflection, Web Bluetooth, Web IDL, Observable, Prioritized Task Scheduling, Shared Storage API, Protected Audience, Web App Launch Handler API, CSS Animation Worklet API, CSS Images 4, CSS Layout API 1, CSS View Transitions 1, CSS View Transitions 2, Federated Credential Management API, Indexed DB 3.0, JSON-LD 1.1 Processing Algorithms and API, Push API, Service Workers, Trusted Types, User Timing, WebAssembly JavaScript Interface, Web Animations 2, Web Locks API, WebRTC Encoded Transform, WebTransport, XMLHttpRequest; see also WebIDLPedia
any (CDDL type) §: Defined in CDDL; Referenced in AT Driver, Web Bluetooth, Prefetch, WebDriver BiDi
any (CSS value for calc-size() ) §: Defined in CSS Values 5
"any" (value for OrientationLockType WebIDL enumeration) §: Defined in Screen Orientation
XPathResult.ANY_TYPE (WebIDL constant) §: Defined in DOM
XPathResult.ANY_UNORDERED_NODE_TYPE (WebIDL constant) §: Defined in DOM
any-hover (CSS descriptor for @media ) §: Defined in Media Queries 4 , Media Queries 5
:any-link (CSS selector) §: Defined in Selectors 4; Referenced in Quirks Mode
any-pointer (CSS descriptor for @media ) §: Defined in Media Queries 4 , Media Queries 5
<any-value> (CSS type) §: Defined in CSS Syntax 3; Referenced in CSS Values 4, CSS Values 5, Media Queries 4, Media Queries 5, Selectors 4
Promise.any(iterable) (WebIDL operation) §: Defined in ECMAScript
TaskSignal.any(signals, init) (WebIDL operation) §: Defined in Prioritized Task Scheduling
AbortSignal.any(signals) (WebIDL operation) §: Defined in DOM
AnyExternType (WebIDL dictionary) §: Defined in WebAssembly JavaScript Interface: Type Reflection; Related terms: AnyExternType.element, AnyExternType.maximum, AnyExternType.minimum, AnyExternType.mutable, AnyExternType.parameters, AnyExternType.results, AnyExternType.value; see also WebIDLPedia
"anyfunc" (value for TableKind WebIDL enumeration) §: Defined in WebAssembly JavaScript Interface: Content Security Policy , WebAssembly JavaScript Interface: ESM Integration , WebAssembly JavaScript Interface: Exception Handling , WebAssembly JavaScript Interface: Promise Integration , WebAssembly JavaScript Interface: JS String Builtins , WebAssembly JavaScript Interface: Type Reflection , WebAssembly JavaScript Interface: Threading , WebAssembly JavaScript Interface
"anyfunc" (value for ValueType WebIDL enumeration) §: Defined in WebAssembly JavaScript Interface: Content Security Policy , WebAssembly JavaScript Interface: ESM Integration , WebAssembly JavaScript Interface: Exception Handling , WebAssembly JavaScript Interface: Promise Integration , WebAssembly JavaScript Interface: JS String Builtins , WebAssembly JavaScript Interface: Type Reflection , WebAssembly JavaScript Interface: Threading , WebAssembly JavaScript Interface
anywhere (CSS value for line-break ) §: Defined in CSS Text 3 , CSS Text 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
anywhere (CSS value for overflow-wrap ) §: Defined in CSS Text 3 , CSS Text 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
API base URL (concept for environment settings object ) §: Defined in HTML; Referenced in Cookie Store API, Fetch, Notifications API, URL Pattern, WebSockets, Content Index, Beacon, CSS Values 4, Image Resource, Service Workers, Web Share API, WebDriver BiDi, WebTransport
app-region (concept) §: Defined in Manifest Incubations
AppBannerPromptOutcome (WebIDL enumeration) §: Defined in Manifest Incubations; Related terms: value accepted, value dismissed; see also WebIDLPedia
NavigatorID.appCodeName (WebIDL attribute) §: Defined in HTML
appear (concept) §: Defined in RDF 1.2 Concepts and Abstract Data Model
appearance (CSS property) §: Defined in CSS User Interface 4; Referenced in CSS Form Control Styling 1, CSS Overflow 5, CSS Typed OM 1; Related terms: CSS type <compat-auto>, CSS type <compat-special>, CSS value auto, CSS value base, CSS value base-select, CSS value button, CSS value checkbox, CSS value listbox, CSS value menulist, CSS value menulist-button, CSS value meter, CSS value none, CSS value progress-bar, CSS value radio, CSS value searchfield, CSS value textarea, CSS value textfield
BluetoothAdvertisingEvent.appearance (WebIDL attribute) §: Defined in Web Bluetooth
BluetoothAdvertisingEventInit.appearance (WebIDL dictionary member) §: Defined in Web Bluetooth
appearance of a cross-fade() (concept) §: Defined in CSS Images 4
append (concept) §: Defined in DOM; Referenced in HTML, Web NFC, Fenced Frame
append (concept for header list ) §: Defined in Fetch; Referenced in Web Share Target API, WebSockets, Client Hints Infrastructure, Shared Storage API, Signature-based Integrity, Loading Signed Exchanges, Content Security Policy: Embedded Enforcement, Device Bound Session Credentials, Service Workers, Upgrade Insecure Requests
append (concept for Headers ) §: Defined in Fetch
append (concept for list ) §: Defined in Infra; Referenced in Console, Cookie Store API, DOM, Encoding, Fetch, File System, HTML, Notifications API, Private Aggregation API, Topics API, Streams, URL, URL Pattern, AT Driver, Long Animation Frames API, Web Share Target API, WebAssembly JavaScript Interface: Content Security Policy, WebAssembly JavaScript Interface: ESM Integration, WebAssembly JavaScript Interface: Exception Handling, WebAssembly JavaScript Interface: Promise Integration, WebAssembly JavaScript Interface: JS String Builtins, WebAssembly JavaScript Interface: Type Reflection, WebAssembly JavaScript Interface: Threading, Web Bluetooth, Web IDL, Translator and Language Detector APIs, Attribution Reporting, Background Fetch, Content Index, Fenced Frame, File System Access, Get Installed Related Apps API, Handwriting Recognition API, Layout Instability API, Local Font Access API, Manifest Incubations, Prefetch, Prerendering Revamped, Observable, Page Lifecycle, Measure Memory API, Web Periodic Background Synchronization, HTML Sanitizer API, URL Fragment Text Directives, Web Serial API, Shared Storage API, Storage Buckets API, Private State Token API, Protected Audience, User-Agent Client Hints, Web Smart Card API, WebHID API, Loading Signed Exchanges, WebUSB API, Web Application Manifest, Clear Site Data, Compute Pressure 1, Contact Picker API, CSS Layout API 1, CSS Painting API 1, CSS Properties and Values API 1, CSS Shadow Parts, CSS Transforms 2, CSS Typed OM 1, CSS View Transitions 1, CSS View Transitions 2, CSS Viewport 1, CSSOM, Federated Credential Management API, Gamepad, Geolocation, Indexed DB 3.0, Media Source Extensions™, MiniApp Manifest, Device Orientation and Motion, Paint Timing, Payment Method Manifest, Performance Timeline, Permissions Policy, Permissions, Privacy-Preserving Attribution 1, Publication Manifest, Push API, Screen Wake Lock API, Secure Payment Confirmation, Server Timing, Service Workers, SRI, WebAssembly JavaScript Interface, Web Locks API, Web Authentication, WebDriver BiDi, WebGPU, Web Neural Network API, WebRTC 1.0, WebXR Device API, Window Management, XMLHttpRequest
append (concept for set ) §: Defined in Infra; Referenced in Cookie Store API, DOM, Fetch, File System, Fullscreen API, HTML, Private Aggregation API, Topics API, Navigational-Tracking Mitigations, Storage, Streams, AT Driver, WebAssembly JavaScript Interface: ESM Integration, Web IDL, Translator and Language Detector APIs, Writing Assistance APIs, Attribution Reporting, Client Hints Infrastructure, Fenced Frame, Keyboard Lock, Observable, HTML Sanitizer API, Prioritized Task Scheduling, Shared Storage API, Signature-based Integrity, Soft Navigations, Protected Audience, Web Smart Card API, Loading Signed Exchanges, Web Application Manifest, Compute Pressure 1, Credential Management 1, Content Security Policy: Embedded Enforcement, Content Security Policy 3, CSS Lists 3, CSS Positioned Layout 4, CSS Properties and Values API 1, CSS View Transitions 1, CSS View Transitions 2, Federated Credential Management API, Generic Sensor API, Indexed DB 3.0, Largest Contentful Paint, Device Orientation and Motion, Paint Timing, Payment Method Manifest, Payment Request API, Privacy-Preserving Attribution 1, Publication Manifest, Service Workers, SRI, Trusted Types, Web Locks API, Web Authentication, WebDriver BiDi, WebGPU, Web Neural Network API, WebRTC Encoded Transform, WebTransport
append an attribute (concept) §: Defined in DOM; Referenced in HTML
append an entry to the contribution cache (concept) §: Defined in Private Aggregation API; Referenced in Protected Audience
append client hints to request (algorithm) §: Defined in Client Hints Infrastructure; Referenced in Responsive Image Client Hints, User-Agent Client Hints
Append Error (concept) §: Defined in Media Source Extensions™
append the Accept-Signature header (algorithm) §: Defined in Signature-based Integrity
append the Fetch metadata headers for a request (algorithm) §: Defined in Fetch Metadata; Referenced in Fetch, Signature-based Integrity
GroupEffect.append(...effects) (WebIDL operation) §: Defined in Web Animations 2
ParentNode.append(...nodes) (WebIDL operation) §: Defined in DOM
SharedStorage.append(key, value, options) (WebIDL operation) §: Defined in Shared Storage API
FormData.append(name, blobValue, filename) (WebIDL operation) §: Defined in XMLHttpRequest
FormData.append(name, value) (WebIDL operation) §: Defined in XMLHttpRequest
Headers.append(name, value) (WebIDL operation) §: Defined in Fetch
URLSearchParams.append(name, value) (WebIDL operation) §: Defined in URL
StylePropertyMap.append(property, ...values) (WebIDL operation) §: Defined in CSS Typed OM 1
SourceBuffer.appendBuffer() (WebIDL operation) §: Defined in Media Source Extensions™
Node.appendChild(node) (WebIDL operation) §: Defined in DOM; Referenced in HTML
CharacterData.appendData(data) (WebIDL operation) §: Defined in DOM
MediaList.appendMedium(medium) (WebIDL operation) §: Defined in CSSOM
AppendMode (WebIDL enumeration) §: Defined in Media Source Extensions™; Related terms: value segments, value sequence; see also WebIDLPedia
CSSKeyframesRule.appendRule(rule) (WebIDL operation) §: Defined in CSS Animations 1
SourceBuffer.appendWindowEnd (WebIDL attribute) §: Defined in Media Source Extensions™
SourceBuffer.appendWindowStart (WebIDL attribute) §: Defined in Media Source Extensions™
AuthenticationExtensionsClientInputs.appid (WebIDL dictionary member) §: Defined in Web Authentication
AuthenticationExtensionsClientInputsJSON.appid (WebIDL dictionary member) §: Defined in Web Authentication
AuthenticationExtensionsClientOutputs.appid (WebIDL dictionary member) §: Defined in Web Authentication
AuthenticationExtensionsClientOutputsJSON.appid (WebIDL dictionary member) §: Defined in Web Authentication
AuthenticationExtensionsClientInputs.appidExclude (WebIDL dictionary member) §: Defined in Web Authentication
AuthenticationExtensionsClientInputsJSON.appidExclude (WebIDL dictionary member) §: Defined in Web Authentication
AuthenticationExtensionsClientOutputs.appidExclude (WebIDL dictionary member) §: Defined in Web Authentication
AuthenticationExtensionsClientOutputsJSON.appidExclude (WebIDL dictionary member) §: Defined in Web Authentication
appinstalled (event) §: Defined in Manifest Incubations
applet (markup element) §: Defined in HTML
Document.applets (WebIDL attribute) §: Defined in HTML
OpusEncoderConfig.application (WebIDL dictionary member) §: Defined in Opus WebCodecs Registration
application context (concept) §: Defined in Web Application Manifest; Referenced in Media Queries 5
Application internal identifiers (concept) §: Defined in Internationalization Glossary
application manifest media type (concept) §: Defined in Web Application Manifest
application-name (value for name attribute of meta element ) §: Defined in HTML
application/manifest+json (concept) §: Defined in Web Application Manifest
application/x-www-form-urlencoded (value for enctype attribute of button element, enctype attribute of form element ) §: Defined in HTML
application/x-www-form-urlencoded (concept) §: Defined in URL; Referenced in The No-Vary-Search HTTP Response Header Field, HTML, Web Share Target API
PushSubscriptionOptions.applicationServerKey (WebIDL attribute) §: Defined in Push API
PushSubscriptionOptionsInit.applicationServerKey (WebIDL dictionary member) §: Defined in Push API
@apply (CSS @rule) §: Defined in CSS Functions and Mixins
Apply glyph keyed patch (algorithm) §: Defined in Incremental Font Transfer
apply request modifiers from URL value (concept) §: Defined in CSS Values 5
Apply table keyed patch (algorithm) §: Defined in Incremental Font Transfer
apply the percent hint (concept) §: Defined in CSS Typed OM 1
apply to (concept for CSS ) §: Defined in CSS Cascading 4 , CSS Cascading 5; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS User Interface 4
Reflect.apply(target, thisArgument, argumentsList) (WebIDL operation) §: Defined in ECMAScript
Function.apply(thisArg, argArray) (WebIDL operation) §: Defined in ECMAScript
ApplyConstraints algorithm (algorithm) §: Defined in Media Capture and Streams
ConstrainablePattern.applyConstraints() (WebIDL operation) §: Defined in Media Capture and Streams
MediaStreamTrack.applyConstraints() (WebIDL operation) §: Defined in Media Capture and Streams; Referenced in MediaStream Image Capture, MediaStreamTrack Insertable Media Processing using Streams
ApplyStringOrNumericBinaryOperator (algorithm) §: Defined in ECMAScript
NavigatorID.appName (WebIDL attribute) §: Defined in HTML
IdentityProviderAccount.approved_clients (WebIDL dictionary member) §: Defined in Federated Credential Management API
NavigatorID.appVersion (WebIDL attribute) §: Defined in HTML; Referenced in WebXR Device API
AppWorkspace (concept) §: Defined in CSS Color 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
AppWorkspace (CSS value for <color>, <deprecated-color> type ) §: Defined in CSS Color 4
aqua (concept) §: Defined in CSS Color 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
aqua (CSS value for <color>, <named-color> type ) §: Defined in CSS Color 4 , CSS 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2025
aquamarine (concept) §: Defined in CSS Color 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
aquamarine (CSS value for <color>, <named-color> type ) §: Defined in CSS Color 4
arabic-indic (CSS value for <counter-style-name> ) §: Defined in CSS Counter Styles 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
arbitrary substitution function (concept) §: Defined in CSS Values 5; Referenced in CSS Variables 2, CSS Anchor Positioning, CSS Functions and Mixins, CSS Variables 1
arc (CSS value for shape() ) §: Defined in CSS Shapes 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025; Related terms: CSS value ccw, CSS value cw, CSS value large, CSS value small
<arc-command> (CSS type for shape() ) §: Defined in CSS Shapes 1
<arc-size> (CSS type for shape() ) §: Defined in CSS Shapes 1
<arc-sweep> (CSS type for shape() ) §: Defined in CSS Shapes 1
CanvasPath.arc(x, y, radius, startAngle, endAngle, counterclockwise) (WebIDL operation) §: Defined in HTML
GPUAdapterInfo.architecture (WebIDL attribute) §: Defined in WebGPU
UADataValues.architecture (WebIDL dictionary member) §: Defined in User-Agent Client Hints
archive (markup attribute for object ) §: Defined in HTML
HTMLObjectElement.archive (WebIDL attribute) §: Defined in HTML
archive MIME type (concept) §: Defined in MIME Sniffing
arcs (CSS value for stroke-linejoin ) §: Defined in CSS Fill and Stroke 3
arcs linejoin (concept) §: Defined in CSS Fill and Stroke 3
CanvasPath.arcTo(x1, y1, x2, y2, radius) (WebIDL operation) §: Defined in HTML
area (markup element) §: Defined in HTML; Referenced in DOM, Attribution Reporting, Prerendering Revamped, EPUB 3.3, EPUB 3.4, HTML Accessibility API Mappings 1.0, ARIA in HTML, Referrer Policy, Selectors 4; Related terms: markup attribute alt, markup attribute attributionsrc, markup attribute coords, markup attribute download, markup attribute href, markup attribute hreflang, markup attribute hreflang, markup attribute nohref, markup attribute ping, markup attribute referrerpolicy, markup attribute rel, markup attribute shape, markup attribute target, markup attribute type, markup attribute type
HTMLMapElement.areas (WebIDL attribute) §: Defined in HTML
arg (markup attribute) §: Defined in MathML Core
MLOpSupportLimits.argMax (WebIDL dictionary member) §: Defined in Web Neural Network API
MLGraphBuilder.argMax(input, axis, options) (WebIDL operation) §: Defined in Web Neural Network API
MLOpSupportLimits.argMin (WebIDL dictionary member) §: Defined in Web Neural Network API
MLGraphBuilder.argMin(input, axis, options) (WebIDL operation) §: Defined in Web Neural Network API
Argon2Params (WebIDL dictionary) §: Defined in Modern Algorithms in the Web Cryptography API; Related terms: Argon2Params.associatedData, Argon2Params.memory, Argon2Params.nonce, Argon2Params.parallelism, Argon2Params.passes, Argon2Params.secretValue, Argon2Params.version; see also WebIDLPedia
CSSParserFunction.args (WebIDL attribute) §: Defined in CSS Parser API
argument grammar (concept) §: Defined in CSS Values 5; Referenced in CSS Variables 2, CSS Functions and Mixins, CSS Variables 1
arguments exotic object (concept for ECMAScript ) §: Defined in ECMAScript
ARIA attributes (concept) §: Defined in SVG 2; Referenced in SVG Paths
ARIAMixin.ariaActiveDescendantElement (WebIDL attribute) §
ARIAMixin.ariaActiveDescendantElement (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaAtomic (WebIDL attribute) §
ARIAMixin.ariaAtomic (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaAutoComplete (WebIDL attribute) §
ARIAMixin.ariaAutoComplete (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaBrailleLabel (WebIDL attribute) §
ARIAMixin.ariaBrailleLabel (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaBrailleRoleDescription (WebIDL attribute) §
ARIAMixin.ariaBrailleRoleDescription (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaBusy (WebIDL attribute) §
ARIAMixin.ariaBusy (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaChecked (WebIDL attribute) §
ARIAMixin.ariaChecked (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaColCount (WebIDL attribute) §
ARIAMixin.ariaColCount (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaColIndex (WebIDL attribute) §
ARIAMixin.ariaColIndex (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaColIndexText (WebIDL attribute) §
ARIAMixin.ariaColIndexText (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaColSpan (WebIDL attribute) §
ARIAMixin.ariaColSpan (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaControlsElements (WebIDL attribute) §
ARIAMixin.ariaControlsElements (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaCurrent (WebIDL attribute) §
ARIAMixin.ariaCurrent (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaDescribedByElements (WebIDL attribute) §
ARIAMixin.ariaDescribedByElements (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaDescription (WebIDL attribute) §
ARIAMixin.ariaDescription (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaDetailsElements (WebIDL attribute) §
ARIAMixin.ariaDetailsElements (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaDisabled (WebIDL attribute) §
ARIAMixin.ariaDisabled (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaErrorMessageElements (WebIDL attribute) §
ARIAMixin.ariaErrorMessageElements (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaExpanded (WebIDL attribute) §
ARIAMixin.ariaExpanded (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaFlowToElements (WebIDL attribute) §
ARIAMixin.ariaFlowToElements (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaHasPopup (WebIDL attribute) §
ARIAMixin.ariaHasPopup (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaHidden (WebIDL attribute) §
ARIAMixin.ariaHidden (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaInvalid (WebIDL attribute) §
ARIAMixin.ariaInvalid (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaKeyShortcuts (WebIDL attribute) §
ARIAMixin.ariaKeyShortcuts (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaLabel (WebIDL attribute) §
ARIAMixin.ariaLabel (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaLabelledByElements (WebIDL attribute) §
ARIAMixin.ariaLabelledByElements (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaLevel (WebIDL attribute) §
ARIAMixin.ariaLevel (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaLive (WebIDL attribute) §
ARIAMixin.ariaLive (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin (WebIDL interface) §: Defined in WAI-ARIA , WAI-ARIA; Related terms: undefinedariaActiveDescendantElement, undefinedariaAtomic, undefinedariaAutoComplete, undefinedariaBrailleLabel, undefinedariaBrailleRoleDescription, undefinedariaBusy, undefinedariaChecked, undefinedariaColCount, undefinedariaColIndex, undefinedariaColIndexText, undefinedariaColSpan, undefinedariaControlsElements, undefinedariaCurrent, undefinedariaDescribedByElements, undefinedariaDescription, undefinedariaDetailsElements, undefinedariaDisabled, undefinedariaErrorMessageElements, undefinedariaExpanded, undefinedariaFlowToElements, undefinedariaHasPopup, undefinedariaHidden, undefinedariaInvalid, undefinedariaKeyShortcuts, undefinedariaLabel, undefinedariaLabelledByElements, undefinedariaLevel, undefinedariaLive, undefinedariaModal, undefinedariaMultiLine, undefinedariaMultiSelectable, undefinedariaOrientation, undefinedariaOwnsElements, undefinedariaPlaceholder, undefinedariaPosInSet, undefinedariaPressed, undefinedariaReadOnly, undefinedariaRelevant, undefinedariaRequired, undefinedariaRoleDescription, undefinedariaRowCount, undefinedariaRowIndex, undefinedariaRowIndexText, undefinedariaRowSpan, undefinedariaSelected, undefinedariaSetSize, undefinedariaSort, undefinedariaValueMax, undefinedariaValueMin, undefinedariaValueNow, undefinedariaValueText, undefinedrole; see also WebIDLPedia
ARIAMixin.ariaModal (WebIDL attribute) §
ARIAMixin.ariaModal (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaMultiLine (WebIDL attribute) §
ARIAMixin.ariaMultiLine (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaMultiSelectable (WebIDL attribute) §
ARIAMixin.ariaMultiSelectable (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaOrientation (WebIDL attribute) §
ARIAMixin.ariaOrientation (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaOwnsElements (WebIDL attribute) §
ARIAMixin.ariaOwnsElements (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaPlaceholder (WebIDL attribute) §
ARIAMixin.ariaPlaceholder (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaPosInSet (WebIDL attribute) §
ARIAMixin.ariaPosInSet (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaPressed (WebIDL attribute) §
ARIAMixin.ariaPressed (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaReadOnly (WebIDL attribute) §
ARIAMixin.ariaReadOnly (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaRelevant (WebIDL attribute) §
ARIAMixin.ariaRelevant (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaRequired (WebIDL attribute) §
ARIAMixin.ariaRequired (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaRoleDescription (WebIDL attribute) §
ARIAMixin.ariaRoleDescription (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaRowCount (WebIDL attribute) §
ARIAMixin.ariaRowCount (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaRowIndex (WebIDL attribute) §
ARIAMixin.ariaRowIndex (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaRowIndexText (WebIDL attribute) §
ARIAMixin.ariaRowIndexText (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaRowSpan (WebIDL attribute) §
ARIAMixin.ariaRowSpan (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaSelected (WebIDL attribute) §
ARIAMixin.ariaSelected (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaSetSize (WebIDL attribute) §
ARIAMixin.ariaSetSize (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaSort (WebIDL attribute) §
ARIAMixin.ariaSort (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaValueMax (WebIDL attribute) §
ARIAMixin.ariaValueMax (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaValueMin (WebIDL attribute) §
ARIAMixin.ariaValueMin (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaValueNow (WebIDL attribute) §
ARIAMixin.ariaValueNow (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
ARIAMixin.ariaValueText (WebIDL attribute) §
ARIAMixin.ariaValueText (WebIDL attribute) §: Defined in WAI-ARIA , WAI-ARIA
arithmetic (value for operator attribute of feComposite ) §: Defined in Filter Effects 1
armenian (CSS value for <counter-style-name> ) §: Defined in CSS Counter Styles 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Speech 1
armenian (CSS value for list-style-type ) §: Defined in CSS 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2025
Array (WebIDL interface) §: Defined in ECMAScript; Referenced in Streams, Accelerated Shape Detection in Images, CSS Viewport 1, Indexed DB 3.0; Related terms: new Array(...values), Array.at(index), Array.concat(...items), Array.copyWithin(target, start, end), Array.entries(), Array.every(callback, thisArg), Array.fill(value, start, end), Array.filter(callback, thisArg), Array.find(predicate, thisArg), Array.findIndex(predicate, thisArg), Array.findLast(predicate, thisArg), Array.findLastIndex(predicate, thisArg), Array.flat(depth), Array.flatMap(mapperFunction, thisArg), Array.forEach(callback, thisArg), Array.from(items, mapper, thisArg), Array.includes(searchElement, fromIndex), Array.indexOf(searchElement, fromIndex), Array.isArray(arg), Array.join(separator), Array.keys(), Array.lastIndexOf(searchElement, fromIndex), Array.map(callback, thisArg), Array.of(...items), Array.pop(), Array.push(...items), Array.reduce(callback, initialValue), Array.reduceRight(callback, initialValue), Array.reverse(), Array.shift(), Array.slice(start, end), Array.some(callback, thisArg), Array.sort(comparator), Array.splice(start, deleteCount, ...items), Array.toLocaleString(reserved1, reserved2), Array.toReversed(), Array.toSorted(comparator), Array.toSpliced(start, skipCount, ...items), Array.toString(), Array.unshift(...items), Array.values(), Array.with(index, value); see also WebIDLPedia
Array exotic object (concept for ECMAScript ) §: Defined in ECMAScript; Referenced in Indexed DB 3.0
array index (concept for ECMAScript ) §: Defined in ECMAScript; Referenced in Web IDL
Array Iterator (concept for ECMAScript ) §: Defined in ECMAScript; Referenced in ECMAScript Async Explicit Resource Management, ECMAScript Explicit Resource Management, Source Phase Imports, Web IDL
array layer count (algorithm) §: Defined in WebGPU
array-like object (concept for ECMAScript ) §: Defined in ECMAScript; Referenced in ECMAScript® 2026 Internationalization API, ES Array.fromAsync, JSON.parse source text access
Array.prototype %Symbol.iterator% () (WebIDL operation for Array.prototype [ %Symbol.iterator% ] ( ) ) §: Defined in ECMAScript
%Array.prototype% (WebIDL interface) §: Defined in ECMAScript; Referenced in HTML, Web IDL; see also WebIDLPedia
new Array(...values) (WebIDL constructor) §: Defined in ECMAScript
%Array% (WebIDL interface) §: Defined in ECMAScript; Referenced in ECMAScript Async Explicit Resource Management, ECMAScript Explicit Resource Management, Source Phase Imports; see also WebIDLPedia
ArrayBuffer (WebIDL interface) §: Defined in Web IDL; Referenced in Encoding, Fetch, CTAP, HTML, Web Bluetooth Scanning, WebSockets, Direct Sockets API, Web Smart Card API, Modern Algorithms in the Web Cryptography API, Secure Curves in the Web Cryptography API, Loading Signed Exchanges, WebUSB API, Web Platform Design Principles, Encrypted Media Extensions, File API, Indexed DB 3.0, Presentation API, Push API, Secure Payment Confirmation, Service Workers, Web Audio API, Web Audio API 1.1, Web Authentication, WebCodecs, Web Cryptography 2, WebGPU, Web Neural Network API, WebRTC Encoded Transform, WebRTC 1.0, WebTransport, WebXR Depth Sensing, XMLHttpRequest; Related terms: concept create, concept detach, concept transfer, concept write, ArrayBuffer.byteLength, ArrayBuffer.detached, ArrayBuffer.maxByteLength, ArrayBuffer.resizable, new ArrayBuffer(length, options), ArrayBuffer.isView(arg), ArrayBuffer.resize(newLength), ArrayBuffer.slice(start, end), ArrayBuffer.transfer(newLength), ArrayBuffer.transferToFixedLength(newLength); see also WebIDLPedia
"arraybuffer" (value for BinaryType WebIDL enumeration) §: Defined in WebSockets; Referenced in WebRTC 1.0
"arraybuffer" (value for XMLHttpRequestResponseType WebIDL enumeration) §: Defined in XMLHttpRequest
%ArrayBuffer.prototype% (WebIDL interface) §: Defined in ECMAScript; see also WebIDLPedia
Blob.arrayBuffer() (WebIDL operation) §: Defined in File API
Body.arrayBuffer() (WebIDL operation) §: Defined in Fetch
PushMessageData.arrayBuffer() (WebIDL operation) §: Defined in Push API
new ArrayBuffer(length, options) (WebIDL constructor) §: Defined in ECMAScript
%ArrayBuffer% (WebIDL interface) §: Defined in ECMAScript; Referenced in Streams, ECMAScript Async Explicit Resource Management, ECMAScript Explicit Resource Management, Source Phase Imports, Web IDL; see also WebIDLPedia
ArrayBufferByteLength (algorithm) §: Defined in ECMAScript
ArrayBufferCopyAndDetach (algorithm) §: Defined in ECMAScript
ArrayBufferView (WebIDL type alias) §: Defined in Web IDL; Referenced in Streams, WebSockets, Presentation API, Web Cryptography 2, Web Neural Network API, WebRTC 1.0; Related terms: concept create, concept write; see also WebIDLPedia
ArrayCreate (algorithm) §: Defined in ECMAScript; Referenced in HTML, ECMAScript® 2026 Internationalization API, ES Array.fromAsync, ECMAScript Async Explicit Resource Management, ECMAScript Explicit Resource Management, Intl.DurationFormat, Temporal, Web IDL
%ArrayIteratorPrototype% (WebIDL interface) §: Defined in ECMAScript; see also WebIDLPedia
GPUTextureViewDescriptor.arrayLayerCount (WebIDL dictionary member) §: Defined in WebGPU
ArraySetLength (algorithm) §: Defined in ECMAScript
ArraySpeciesCreate (algorithm) §: Defined in ECMAScript
GPUVertexBufferLayout.arrayStride (WebIDL dictionary member) §: Defined in WebGPU
article (markup element) §: Defined in HTML; Referenced in HTML Accessibility API Mappings 1.0, ARIA in HTML, WAI-ARIA, WAI-ARIA
"article" (value for ContentCategory WebIDL enumeration) §: Defined in Content Index
MediaMetadata.artist (WebIDL attribute) §: Defined in Media Session
MediaMetadataInit.artist (WebIDL dictionary member) §: Defined in Media Session
ChapterInformation.artwork (WebIDL attribute) §: Defined in Media Session
ChapterInformationInit.artwork (WebIDL dictionary member) §: Defined in Media Session
MediaMetadata.artwork (WebIDL attribute) §: Defined in Media Session
MediaMetadataInit.artwork (WebIDL dictionary member) §: Defined in Media Session
as (markup attribute for link ) §: Defined in HTML; Referenced in HTML Accessibility API Mappings 1.0
HTMLLinkElement.as (WebIDL attribute) §: Defined in HTML
as a body (concept for byte sequence ) §: Defined in Fetch; Referenced in HTML, Signature-based Integrity, WebDriver BiDi
"as-is" (value for RewriterTone WebIDL enumeration) §: Defined in Writing Assistance APIs
"as-is" (value for RewriterLength WebIDL enumeration) §: Defined in Writing Assistance APIs
"as-is" (value for RewriterFormat WebIDL enumeration) §: Defined in Writing Assistance APIs
ascent-override (CSS descriptor for @font-face ) §: Defined in CSS Fonts 4 , CSS Fonts 5
CSSFontFaceDescriptors.ascent-override (WebIDL attribute) §
CSSFontFaceDescriptors.ascent-override (WebIDL attribute) §: Defined in CSS Fonts 4 , CSS Fonts 5
CSSFontFaceDescriptors.ascentOverride (WebIDL attribute) §
CSSFontFaceDescriptors.ascentOverride (WebIDL attribute) §: Defined in CSS Fonts 4 , CSS Fonts 5
FontFace.ascentOverride (WebIDL attribute) §: Defined in CSS Font Loading 3
FontFaceDescriptors.ascentOverride (WebIDL dictionary member) §: Defined in CSS Font Loading 3
ASCII alpha (concept) §: Defined in Infra; Referenced in DOM, HTML, URL, User-Agent Client Hints
ASCII alphanumeric (concept) §: Defined in Infra; Referenced in HTML, MIME Sniffing, URL, Web NFC, File System Access, WebDriver BiDi
ASCII byte (concept) §: Defined in Infra; Referenced in Encoding, URL, Protected Audience, User-Agent Client Hints, Loading Signed Exchanges
ASCII case-insensitive (concept) §: Defined in Infra; Referenced in DOM, CSS Variables 2, Encoding, Fetch, HTML, MIME Sniffing, URL, execCommand, Web Share Target API, Fenced Frame, Isolated Contexts, Credential Management 1, Content Security Policy: Embedded Enforcement, Content Security Policy 3, CSS Color 3, CSS Color 4, CSS Color 5, CSS Conditional 3, CSS Counter Styles 3, CSS Fonts 4, CSS Properties and Values API 1, CSS Syntax 3, CSS Typed OM 1, CSS Values 3, CSS Values 4, CSS Values 5, CSS Variables 1, CSS Will Change 1, CSSOM, ARIA in HTML, Internationalization Glossary, MathML Core, MathML 4.0, Media Queries 3, Media Queries 4, Media Queries 5, Media Session, Payment Method Manifest, Permissions Policy, Publication Manifest, Selection API, Selectors 4, Service Workers, Trace Context 2, WebRTC 1.0, WebTransport, WoT Architecture 1.1, XMLHttpRequest
ASCII case-insensitive (concept) §: Defined in Internationalization Glossary
ASCII code point (concept) §: Defined in Infra; Referenced in Encoding, URL, URL Pattern, Shared Storage API, Protected Audience, Propagation format for distributed context: Baggage, Web Platform Design Principles
ASCII decode (concept) §: Defined in Infra; Referenced in Web NFC, Loading Signed Exchanges
ASCII digit (concept) §: Defined in Infra; Referenced in DOM, Fetch, HTML, URL, URL Pattern, Storage Buckets API, Protected Audience, Content Security Policy 3, Digital Credentials, WebDriver BiDi
ASCII encode (concept) §: Defined in Infra; Referenced in Protected Audience, Loading Signed Exchanges
ASCII hex digit (concept) §: Defined in Infra; Referenced in HTML, URL, URL Pattern, Web NFC, Attribution Reporting
ASCII lower alpha (concept) §: Defined in Infra; Referenced in HTML, Storage Buckets API, Protected Audience, Digital Credentials
ASCII lower hex digit (concept) §: Defined in Infra; Referenced in HTML, Web Bluetooth, Protected Audience, CSS Color 4, Web Cryptography 2
ASCII lowercase (concept) §: Defined in Infra; Referenced in DOM, Encoding, HTML, MIME Sniffing, URL, URL Pattern, AT Driver, Web Share Target API, Attribution Reporting, Signature-based Integrity, Protected Audience, Web Application Manifest, Content Security Policy 3, CSS Color 4, CSS Color HDR 1, CSS Typed OM 1, CSSOM, File API, ARIA in HTML, MathML Core, Permissions, SRI, Trace Context 2, Trusted Types, WebDriver BiDi, WebDriver
ASCII string (concept) §: Defined in Infra; Referenced in Fetch, HTML, MIME Sniffing, Storage, URL, URL Pattern, URL Fragment Text Directives, Shared Storage API, Loading Signed Exchanges, Content Security Policy 3, DID Resolution; Related terms: concept code point length, concept length
ASCII tab or newline (concept) §: Defined in Infra; Referenced in HTML, URL
ASCII upper alpha (concept) §: Defined in Infra; Referenced in HTML, Protected Audience, Loading Signed Exchanges
ASCII upper hex digit (concept) §: Defined in Infra; Referenced in HTML, URL
ASCII uppercase (concept) §: Defined in Infra; Referenced in DOM, HTML, Web Share Target API, CSSOM, Payment Request API
ASCII whitespace (concept) §: Defined in Infra; Referenced in DOM, Encoding, Fetch, HTML, MIME Sniffing, SMS One-Time Codes, Accessible Name and Description Computation 1.2, Content Security Policy 3, EPUB 3.3, EPUB 3.4, WAI-ARIA, WAI-ARIA, WebVTT: The Web Video Text Tracks Format
aside (markup element) §: Defined in HTML; Referenced in HTML Accessibility API Mappings 1.0, ARIA in HTML, WAI-ARIA, WAI-ARIA
asin() (CSS function) §: Defined in CSS Values 4
Math.asin(x) (WebIDL operation) §: Defined in ECMAScript
Math.asinh(x) (WebIDL operation) §: Defined in ECMAScript
BigInt.asIntN(bits, bigint) (WebIDL operation) §: Defined in ECMAScript
ask the user to choose a Credential (algorithm) §: Defined in Credential Management 1
GPUTexelCopyTextureInfo.aspect (WebIDL dictionary member) §: Defined in WebGPU
GPUTextureViewDescriptor.aspect (WebIDL dictionary member) §: Defined in WebGPU
aspect-ratio (CSS descriptor for @container ) §: Defined in CSS Conditional 5
aspect-ratio (CSS property) §: Defined in CSS Sizing 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Containment 1, CSS Containment 2, CSS Flexbox 1; Related terms: CSS value auto, CSS value auto && <ratio>
aspect-ratio (CSS descriptor for @media ) §: Defined in Media Queries 4 , Media Queries 5; Referenced in CSSOM
aspectRatio (concept) §: Defined in Screen Capture
MediaTrackCapabilities.aspectRatio (WebIDL dictionary member) §: Defined in Media Capture and Streams
MediaTrackConstraintSet.aspectRatio (WebIDL dictionary member) §: Defined in Media Capture and Streams
MediaTrackSettings.aspectRatio (WebIDL dictionary member) §: Defined in Media Capture and Streams
MediaTrackSupportedConstraints.aspectRatio (WebIDL dictionary member) §: Defined in Media Capture and Streams
XRCylinderLayer.aspectRatio (WebIDL attribute) §: Defined in WebXR Layers API 1
XRCylinderLayerInit.aspectRatio (WebIDL dictionary member) §: Defined in WebXR Layers API 1
XRMediaCylinderLayerInit.aspectRatio (WebIDL dictionary member) §: Defined in WebXR Layers API 1
assemble primitives (algorithm) §: Defined in WebGPU
Assert (concept) §: Defined in Infra; Referenced in DOM, Encoding, Fetch, File System, HTML, Private Aggregation API, Topics API, Navigational-Tracking Mitigations, The Storage Access API, URL, URL Pattern, AT Driver, Web IDL, Translator and Language Detector APIs, Writing Assistance APIs, Attribution Reporting, Fenced Frame, Local Network Access, Prefetch, Prerendering Revamped, Observable, Measure Memory API, Web Periodic Background Synchronization, Portals, HTML Sanitizer API, URL Fragment Text Directives, Shared Storage API, Private State Token API, Protected Audience, User-Agent Client Hints, Web App Launch Handler API, Web Smart Card API, Modern Algorithms in the Web Cryptography API, WebUSB API, Audio Session, Compute Pressure 1, CSS Spatial Navigation 1, CSS View Transitions 1, CSS View Transitions 2, File API, Gamepad, Generic Sensor API, Geolocation, High Resolution Time, Indexed DB 3.0, MathML Core, Payment Request API, Presentation API, Privacy-Preserving Attribution 1, Push API, Referrer Policy, Screen Orientation, SRI, Trusted Types, Web Locks API, Web Share API, WebDriver BiDi, WebGPU, Web Neural Network API
console.assert(condition, ...data) (WebIDL operation) §: Defined in Console
asserted triple (concept) §: Defined in RDF 1.2 Concepts and Abstract Data Model
RTCIdentityAssertionResult.assertion (WebIDL dictionary member) §: Defined in Identity for WebRTC 1.0
HTMLSlotElement.assign(...nodes) (WebIDL operation) §: Defined in HTML
Object.assign(target, ...sources) (WebIDL operation) §: Defined in ECMAScript
Location.assign(url) (WebIDL operation) §: Defined in HTML
assigned (concept for slottable ) §: Defined in DOM
assigned nodes (concept for slot ) §: Defined in DOM; Referenced in HTML, Accessible Name and Description Computation 1.2
assigned slot (concept for slottable ) §: Defined in DOM; Referenced in HTML
HTMLSlotElement.assignedElements(options) (WebIDL operation) §: Defined in HTML
HTMLSlotElement.assignedNodes(options) (WebIDL operation) §: Defined in HTML; Referenced in CSS Scoping 1
AssignedNodesOptions (WebIDL dictionary) §: Defined in HTML; see also WebIDLPedia
Slottable.assignedSlot (WebIDL attribute) §: Defined in DOM
Assistive Technologies (concept) §: Defined in WAI-ARIA , WAI-ARIA
associated Bluetooth (concept) §: Defined in Web Bluetooth; Referenced in Web Bluetooth Scanning
associated CSS style sheet (concept) §: Defined in CSSOM
associated Document (concept) §: Defined in HTML; Referenced in Compatibility, DOM, Fetch, Navigational-Tracking Mitigations, requestStorageAccessFor API, Extending Storage Access API to non-cookie storage, Storage, Login Status API, The Capture-Handle Actions Mechanism, Captured Surface Control, Web Speech API, Web Bluetooth, Web Bluetooth Scanning, Translator and Language Detector APIs, Writing Assistance APIs, Playout Statistics API for WebAudio, Direct Sockets API, Document Picture-in-Picture, Fenced Frame, Idle Detection API, Local Font Access API, Prerendering Revamped, Observable, Web Serial API, Shared Storage API, Soft Navigations, Protected Audience, User-Agent Client Hints, Web Smart Card API, WebHID API, WebUSB API, Badging API, Battery Status API, Compute Pressure 1, Credential Management 1, Content Security Policy 3, CSS Color Adjustment 1, CSS Custom Highlight API 1, CSS Properties and Values API 1, CSS View Transitions 1, CSS View Transitions 2, CSSOM, CSSOM View, Device Posture API, Digital Credentials, Encrypted Media Extensions, Event Timing API, Federated Credential Management API, Mitigating Browser Fingerprinting in Web Specifications, Gamepad, Geolocation, Media Capture and Streams, Viewport Capture, Media Queries 5, Media Session, Navigation Timing 2, Device Orientation and Motion, Paint Timing, Payment Request API, Performance Timeline, Permissions Policy, Permissions, Privacy-Preserving Attribution 1, Push API, Screen Capture, Screen Orientation, Screen Wake Lock API, Service Workers, SRI, Web Locks API, Web Share API, Web Audio API, Web Audio API 1.1, WebDriver BiDi, WebDriver, Web Neural Network API, Window Management, XMLHttpRequest
associated effect (concept for animation ) §: Defined in Web Animations; Referenced in CSS Animations 2, CSS Transitions 2, CSS View Transitions 1, CSS View Transitions 2, Web Animations 2
associated realm (concept) §: Defined in Web IDL; Referenced in DOM, HTML, WebAssembly JavaScript Interface: Content Security Policy, WebAssembly JavaScript Interface: ESM Integration, WebAssembly JavaScript Interface: Exception Handling, WebAssembly JavaScript Interface: Promise Integration, WebAssembly JavaScript Interface: JS String Builtins, WebAssembly JavaScript Interface: Type Reflection, Shared Storage API, WebAssembly JavaScript Interface
associated user context (concept) §: Defined in WebDriver BiDi
Argon2Params.associatedData (WebIDL dictionary member) §: Defined in Modern Algorithms in the Web Cryptography API
CSSStyleValue.[[associatedProperty]] (internal slot) §: Defined in CSS Typed OM 1; Referenced in CSS Properties and Values API 1
association steps (algorithm for RTCRtpTransform ) §: Defined in WebRTC Encoded Transform
"astc-10x10-unorm" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-10x10-unorm-srgb" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-10x5-unorm" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-10x5-unorm-srgb" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-10x6-unorm" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-10x6-unorm-srgb" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-10x8-unorm" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-10x8-unorm-srgb" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-12x10-unorm" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-12x10-unorm-srgb" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-12x12-unorm" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-12x12-unorm-srgb" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-4x4-unorm" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-4x4-unorm-srgb" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-5x4-unorm" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-5x4-unorm-srgb" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-5x5-unorm" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-5x5-unorm-srgb" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-6x5-unorm" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-6x5-unorm-srgb" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-6x6-unorm" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-6x6-unorm-srgb" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-8x5-unorm" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-8x5-unorm-srgb" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-8x6-unorm" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-8x6-unorm-srgb" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-8x8-unorm" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
"astc-8x8-unorm-srgb" (value for GPUTextureFormat WebIDL enumeration) §: Defined in WebGPU
BigInt.asUintN(bits, bigint) (WebIDL operation) §: Defined in ECMAScript
async (value for decoding attribute of img element ) §: Defined in HTML
async (markup attribute for script ) §: Defined in HTML; Referenced in HTML Accessibility API Mappings 1.0, Trusted Types
HTMLScriptElement.async (WebIDL attribute) §: Defined in HTML
async iterable interface (concept for ECMAScript ) §: Defined in ECMAScript; Referenced in Streams
async iterator (concept) §: Defined in Web IDL
async iterator interface (concept for ECMAScript ) §: Defined in ECMAScript
async sequence type (concept) §: Defined in Web IDL
async_sequence (concept) §: Defined in Web IDL
Async-from-Sync Iterator object (concept for ECMAScript ) §: Defined in ECMAScript; Referenced in ECMAScript Async Explicit Resource Management, ECMAScript Explicit Resource Management, Source Phase Imports
AsyncBlockStart (algorithm) §: Defined in ECMAScript; Referenced in ECMAScript Explicit Resource Management
AsyncFromSyncIteratorContinuation (algorithm) §: Defined in ECMAScript
%AsyncFromSyncIteratorPrototype% (WebIDL interface) §: Defined in ECMAScript; see also WebIDLPedia
AsyncFunction (WebIDL interface) §: Defined in ECMAScript; Related terms: new AsyncFunction(...parameterArgs, bodyArg); see also WebIDLPedia
%AsyncFunction.prototype% (WebIDL interface) §: Defined in ECMAScript; Referenced in ECMAScript Async Explicit Resource Management, ECMAScript Explicit Resource Management; see also WebIDLPedia
new AsyncFunction(...parameterArgs, bodyArg) (WebIDL constructor) §: Defined in ECMAScript
%AsyncFunction% (WebIDL interface) §: Defined in ECMAScript; Referenced in ECMAScript Async Explicit Resource Management, ECMAScript Explicit Resource Management, Source Phase Imports; see also WebIDLPedia
AsyncFunctionStart (algorithm) §: Defined in ECMAScript; Referenced in WebAssembly JavaScript Interface: Promise Integration
AsyncGenerator (WebIDL interface) §: Defined in ECMAScript; Referenced in Streams, Source Phase Imports; see also WebIDLPedia
AsyncGeneratorAwaitReturn (algorithm) §: Defined in ECMAScript
AsyncGeneratorCompleteStep (algorithm) §: Defined in ECMAScript; Referenced in ECMAScript Async Explicit Resource Management
AsyncGeneratorDrainQueue (algorithm) §: Defined in ECMAScript; Referenced in ECMAScript Async Explicit Resource Management
AsyncGeneratorEnqueue (algorithm) §: Defined in ECMAScript
AsyncGeneratorFunction (WebIDL interface) §: Defined in ECMAScript; Related terms: AsyncGeneratorFunction.prototype, new AsyncGeneratorFunction(...parameterArgs, bodyArg); see also WebIDLPedia
%AsyncGeneratorFunction.prototype.prototype% (WebIDL interface) §: Defined in ECMAScript; Referenced in ECMAScript Async Explicit Resource Management, ECMAScript Explicit Resource Management; see also WebIDLPedia
%AsyncGeneratorFunction.prototype% (WebIDL interface) §: Defined in ECMAScript; Referenced in ECMAScript Async Explicit Resource Management, ECMAScript Explicit Resource Management; see also WebIDLPedia
new AsyncGeneratorFunction(...parameterArgs, bodyArg) (WebIDL constructor) §: Defined in ECMAScript
%AsyncGeneratorFunction% (WebIDL interface) §: Defined in ECMAScript; Referenced in ECMAScript Async Explicit Resource Management, ECMAScript Explicit Resource Management, Source Phase Imports; see also WebIDLPedia
%AsyncGeneratorPrototype% (WebIDL interface) §: Defined in ECMAScript; see also WebIDLPedia
%AsyncGeneratorPrototype%.next(value) (WebIDL operation for %AsyncGeneratorPrototype%.next ( value ) ) §: Defined in ECMAScript
%AsyncGeneratorPrototype%.return(value) (WebIDL operation for %AsyncGeneratorPrototype%.return ( value ) ) §: Defined in ECMAScript
%AsyncGeneratorPrototype%.throw(exception) (WebIDL operation for %AsyncGeneratorPrototype%.throw ( exception ) ) §: Defined in ECMAScript
AsyncGeneratorRequest (concept for ECMAScript ) §: Defined in ECMAScript
AsyncGeneratorResume (algorithm) §: Defined in ECMAScript
AsyncGeneratorStart (algorithm) §: Defined in ECMAScript
AsyncGeneratorUnwrapYieldResumption (algorithm) §: Defined in ECMAScript
AsyncGeneratorValidate (algorithm) §: Defined in ECMAScript
AsyncGeneratorYield (algorithm) §: Defined in ECMAScript
asynchronous iterator initialization steps (concept) §: Defined in Web IDL; Referenced in File System, Streams, Shared Storage API
asynchronous iterator prototype object (concept) §: Defined in Web IDL
asynchronous iterator return (concept) §: Defined in Web IDL; Referenced in Streams
Asynchronous RP ID validation algorithm (algorithm) §: Defined in Web Authentication
asynchronously iterable declaration (concept) §: Defined in Web IDL
Symbol.asyncIterator (WebIDL attribute) §: Defined in ECMAScript
AsyncIteratorClose (algorithm) §: Defined in ECMAScript; Referenced in ES Array.fromAsync, ECMAScript Async Explicit Resource Management, ECMAScript Explicit Resource Management, Observable
%AsyncIteratorPrototype% (WebIDL interface) §: Defined in ECMAScript; Referenced in ECMAScript Async Explicit Resource Management, ECMAScript Explicit Resource Management, Source Phase Imports, Web IDL; see also WebIDLPedia
AsyncModuleExecutionFulfilled (algorithm) §: Defined in ECMAScript; Referenced in Deferred Imports Evaluation, Source Phase Imports
AsyncModuleExecutionRejected (algorithm) §: Defined in ECMAScript; Referenced in Deferred Imports Evaluation
FileSystemReadWriteOptions.at (WebIDL dictionary member) §: Defined in File System
at <position> (CSS value for ray() ) §: Defined in Motion Path 1
at risk (concept) §: Defined in W3C Process Document; Referenced in CSS Overflow 4, Dubbing and Audio description Profiles of TTML2, Device Orientation and Motion
Event.AT_TARGET (WebIDL constant) §: Defined in DOM; Referenced in UI Events
<at-keyword-token> (CSS type) §: Defined in CSS Syntax 3; Referenced in CSS Functions and Mixins, CSS Values 4
at-rule (concept) §: Defined in CSS Syntax 3; Referenced in Compatibility, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Cascading 5, CSS Cascading 6, CSS Conditional 3, CSS Counter Styles 3, CSS Environment Variables 1, CSS Fonts 4, CSS Namespaces 3, CSS Nesting, CSS Paged Media 3, CSS Scoping 1, CSS Values 4
<at-rule-list> (CSS type) §: Defined in CSS Syntax 3
%TypedArray%.at(index) (WebIDL operation) §: Defined in ECMAScript
Array.at(index) (WebIDL operation) §: Defined in ECMAScript
String.at(index) (WebIDL operation) §: Defined in ECMAScript
atan() (CSS function) §: Defined in CSS Values 4
Math.atan(x) (WebIDL operation) §: Defined in ECMAScript
atan2() (CSS function) §: Defined in CSS Values 4
Math.atan2(y, x) (WebIDL operation) §: Defined in ECMAScript
Math.atanh(x) (WebIDL operation) §: Defined in ECMAScript
WindowOrWorkerGlobalScope.atob(data) (WebIDL operation) §: Defined in HTML
atomic inline (concept) §: Defined in CSS Display 3 , CSS Display 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Containment 1, CSS Containment 2, CSS Inline Layout 3, CSS Layout API 1, CSS Ruby Annotation Layout 1, CSS Scroll Anchoring 1, CSS Text 3, CSS Text 4, CSS Text Decoration 3, CSS Text Decoration 4
<atomic-condition> (CSS type) §: Defined in CSS Conditional Values 1
AtomicCompareExchangeInSharedBlock (algorithm) §: Defined in ECMAScript
AtomicReadModifyWrite (algorithm) §: Defined in ECMAScript
Atomics (WebIDL namespace) §: Defined in ECMAScript; Related terms: Atomics.add(typedArray, index, value), Atomics.and(typedArray, index, value), Atomics.compareExchange(typedArray, index, expectedValue, replacementValue), Atomics.exchange(typedArray, index, value), Atomics.isLockFree(size), Atomics.load(typedArray, index), Atomics.notify(typedArray, index, count), Atomics.or(typedArray, index, value), Atomics.store(typedArray, index, value), Atomics.sub(typedArray, index, value), Atomics.wait(typedArray, index, value, timeout), Atomics.waitAsync(typedArray, index, value, timeout), Atomics.xor(typedArray, index, value)
%Atomics% (WebIDL namespace) §: Defined in ECMAScript; Referenced in HTML, ECMAScript Async Explicit Resource Management, ECMAScript Explicit Resource Management, Source Phase Imports
WebTransportWriter.atomicWrite(chunk) (WebIDL operation) §: Defined in WebTransport
WebTransportSendStream.[[AtomicWriteRequests]] (internal slot) §: Defined in WebTransport
atop (value for operator attribute of feComposite ) §: Defined in Filter Effects 1
MLGemmOptions.aTranspose (WebIDL dictionary member) §: Defined in Web Neural Network API
CSSParserOptions.atRules (WebIDL dictionary member) §: Defined in CSS Parser API
WebTransportConnectionStats.atSendCapacity (WebIDL dictionary member) §: Defined in WebTransport
attached (concept) §: Defined in SVG 2
EditContext.attachedElements() (WebIDL operation) §: Defined in EditContext API
HTMLElement.attachInternals() (WebIDL operation) §: Defined in HTML
<attachment> (CSS type) §: Defined in CSS Backgrounds 4 , CSS Backgrounds 3
"attachment" (value for PresentationStyle WebIDL enumeration) §: Defined in Clipboard API and events
GPURenderPassEncoder.[[attachment_size]] (internal slot) §: Defined in WebGPU
Element.attachShadow(init) (WebIDL operation) §: Defined in DOM; Referenced in HTML
DynamicsCompressorNode.attack (WebIDL attribute) §
DynamicsCompressorNode.attack (WebIDL attribute) §: Defined in Web Audio API , Web Audio API 1.1
DynamicsCompressorOptions.attack (WebIDL dictionary member) §
DynamicsCompressorOptions.attack (WebIDL dictionary member) §: Defined in Web Audio API , Web Audio API 1.1
attempted custom url report to disallowed origin (concept for fenced frame reporting metadata ) §: Defined in Fenced Frame
attempts (concept for report ) §: Defined in Reporting API; Referenced in Network Reporting API
PublicKeyCredentialCreationOptions.attestation (WebIDL dictionary member) §: Defined in Web Authentication
PublicKeyCredentialCreationOptionsJSON.attestation (WebIDL dictionary member) §: Defined in Web Authentication
attestationClientDataJSON (algorithm for credential record ) §: Defined in Web Authentication
AttestationConveyancePreference (WebIDL enumeration) §: Defined in Web Authentication; Related terms: value direct, value enterprise, value indirect, value none; see also WebIDLPedia
PublicKeyCredentialCreationOptions.attestationFormats (WebIDL dictionary member) §: Defined in Web Authentication
PublicKeyCredentialCreationOptionsJSON.attestationFormats (WebIDL dictionary member) §: Defined in Web Authentication
attestationObject (algorithm for credential record ) §: Defined in Web Authentication
AuthenticatorAttestationResponse.attestationObject (WebIDL attribute) §: Defined in Web Authentication
AuthenticatorAttestationResponseJSON.attestationObject (WebIDL dictionary member) §: Defined in Web Authentication
Attr (WebIDL interface) §: Defined in DOM; Referenced in WebDriver BiDi; Related terms: concept element, concept local name, concept namespace, concept namespace prefix, concept qualified name, concept value, Attr.isId, Attr.localName, Attr.name, Attr.namespaceURI, Attr.ownerElement, Attr.prefix, Attr.schemaTypeInfo, Attr.specified, Attr.value; see also WebIDLPedia
<attr-args> (CSS type) §: Defined in CSS Values 5
<attr-name> (CSS type) §: Defined in CSS Values 5
<attr-type> (CSS type) §: Defined in CSS Values 5
<attr-unit> (CSS type) §: Defined in CSS Values 5
::attr() (CSS selector) §: Defined in Non-element Selectors 1
attr() (CSS function) §: Defined in CSS Values 5; Referenced in CSS GCPM 4, CSS Generated Content 3, CSS GCPM 3, CSS Functions and Mixins, CSS Syntax 3, CSS Values 3, CSS Values 4; Related terms: CSS function type()
attr()-taint (concept) §: Defined in CSS Values 5
attr(X) (CSS value for content ) §: Defined in CSS 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2025
attribute (concept) §: Defined in DOM; Referenced in MathML Accessibility API Mappings 1.0, HTML Sanitizer API, Accessible Name and Description Computation 1.2, Core Accessibility API Mappings 1.2, CSS Values 5, WAI-ARIA, WAI-ARIA
attribute (concept) §: Defined in Web IDL; Referenced in Private Aggregation API, Long Animation Frames API, Generic Sensor API
attribute change steps (concept) §: Defined in DOM; Referenced in HTML, Scripting Policy, Fenced Frame, Prerendering Revamped, CSSOM
attribute getter (concept) §: Defined in Web IDL
attribute list (concept for Element ) §: Defined in DOM; Referenced in HTML, HTML Sanitizer API, Content Security Policy 3, WebDriver BiDi
attribute list (concept for NamedNodeMap ) §: Defined in DOM
attribute node selector (concept) §: Defined in Non-element Selectors 1
attribute selector (concept) §: Defined in Selectors 4; Referenced in Quirks Mode, CSS Values 5, WebVTT: The Web Video Text Tracks Format
attribute setter (concept) §: Defined in Web IDL
Node.ATTRIBUTE_NODE (WebIDL constant) §: Defined in DOM
<attribute-selector> (CSS type) §: Defined in Selectors 4
MutationObserverInit.attributeFilter (WebIDL dictionary member) §: Defined in DOM
Bluetooth.[[attributeInstanceMap]] (internal slot) §: Defined in Web Bluetooth
MutationRecord.attributeName (WebIDL attribute) §: Defined in DOM
attributeName (markup attribute for animate ) §: Defined in SVG Animations 2; Referenced in SVG 2
MutationRecord.attributeNamespace (WebIDL attribute) §: Defined in DOM
MutationObserverInit.attributeOldValue (WebIDL dictionary member) §: Defined in DOM
Element.attributes (WebIDL attribute) §: Defined in DOM
GPUVertexBufferLayout.attributes (WebIDL dictionary member) §: Defined in WebGPU
MutationObserverInit.attributes (WebIDL dictionary member) §: Defined in DOM
SanitizerConfig.attributes (WebIDL dictionary member) §: Defined in HTML Sanitizer API
SanitizerElementNamespaceWithAttributes.attributes (WebIDL dictionary member) §: Defined in HTML Sanitizer API
ElementCSSInlineStyle.attributeStyleMap (WebIDL attribute) §: Defined in CSS Typed OM 1
MemoryBreakdownEntry.attribution (WebIDL dictionary member) §: Defined in Measure Memory API
Navigator.attribution (WebIDL attribute) §: Defined in Privacy-Preserving Attribution 1
PerformanceLongTaskTiming.attribution (WebIDL attribute) §: Defined in Long Tasks API
Attribution (WebIDL interface) §: Defined in Privacy-Preserving Attribution 1; Related terms: Attribution.aggregationServices, Attribution.measureConversion(options), Attribution.saveImpression(options); see also WebIDLPedia
Attribution Reporting eligibility (concept for request ) §: Defined in Attribution Reporting; Referenced in Fenced Frame
"attribution-reporting" (value for PermissionPolicy WebIDL enumeration) §: Defined in Attribution Reporting; Referenced in Fenced Frame, Protected Audience
AttributionAggregationProtocol (WebIDL enumeration) §: Defined in Privacy-Preserving Attribution 1; Related terms: value dap-15-histogram, value tee-00; see also WebIDLPedia
AttributionAggregationService (WebIDL dictionary) §: Defined in Privacy-Preserving Attribution 1; Related terms: AttributionAggregationService.protocol; see also WebIDLPedia
AttributionAggregationServices (WebIDL interface) §: Defined in Privacy-Preserving Attribution 1; see also WebIDLPedia
AttributionConversionOptions (WebIDL dictionary) §: Defined in Privacy-Preserving Attribution 1; Related terms: AttributionConversionOptions.aggregationService, AttributionConversionOptions.credit, AttributionConversionOptions.epsilon, AttributionConversionOptions.histogramSize, AttributionConversionOptions.impressionCallers, AttributionConversionOptions.impressionSites, AttributionConversionOptions.lookbackDays, AttributionConversionOptions.matchValues, AttributionConversionOptions.maxValue, AttributionConversionOptions.value; see also WebIDLPedia
AttributionConversionResult (WebIDL dictionary) §: Defined in Privacy-Preserving Attribution 1; Related terms: AttributionConversionResult.report; see also WebIDLPedia
HTMLAnchorElement.attributionDestination (WebIDL attribute) §: Defined in Private Click Measurement
AttributionImpressionOptions (WebIDL dictionary) §: Defined in Privacy-Preserving Attribution 1; Related terms: AttributionImpressionOptions.conversionCallers, AttributionImpressionOptions.conversionSites, AttributionImpressionOptions.histogramIndex, AttributionImpressionOptions.lifetimeDays, AttributionImpressionOptions.matchValue, AttributionImpressionOptions.priority; see also WebIDLPedia
AttributionImpressionResult (WebIDL dictionary) §: Defined in Privacy-Preserving Attribution 1; see also WebIDLPedia
RequestInit.attributionReporting (WebIDL dictionary member) §: Defined in Attribution Reporting
AttributionReportingRequestOptions (WebIDL dictionary) §: Defined in Attribution Reporting; Related terms: AttributionReportingRequestOptions.eventSourceEligible, AttributionReportingRequestOptions.triggerEligible; see also WebIDLPedia
HTMLAnchorElement.attributionSourceId (WebIDL attribute) §: Defined in Private Click Measurement
HTMLAttributionSrcElementUtils.attributionSrc (WebIDL attribute) §: Defined in Attribution Reporting
attributionsrc (markup attribute for a ) §: Defined in Attribution Reporting
attributionsrc (markup attribute for area ) §: Defined in Attribution Reporting
attributionsrc (markup attribute for img ) §: Defined in Attribution Reporting
attributionsrc (markup attribute for script ) §: Defined in Attribution Reporting
auction config (concept) §: Defined in Protected Audience
AuctionAd (WebIDL dictionary) §: Defined in Protected Audience; Related terms: AuctionAd.adRenderId, AuctionAd.allowedReportingOrigins, AuctionAd.buyerAndSellerReportingId, AuctionAd.buyerReportingId, AuctionAd.creativeScanningMetadata, AuctionAd.metadata, AuctionAd.renderURL, AuctionAd.selectableBuyerAndSellerReportingIds, AuctionAd.sizeGroup; see also WebIDLPedia
AuctionAdConfig (WebIDL dictionary) §: Defined in Protected Audience; Related terms: AuctionAdConfig.additionalBids, AuctionAdConfig.allSlotsRequestedSizes, AuctionAdConfig.auctionNonce, AuctionAdConfig.auctionReportBuyerDebugModeConfig, AuctionAdConfig.auctionReportBuyerKeys, AuctionAdConfig.auctionReportBuyers, AuctionAdConfig.auctionSignals, AuctionAdConfig.componentAuctions, AuctionAdConfig.decisionLogicURL, AuctionAdConfig.deprecatedRenderURLReplacements, AuctionAdConfig.directFromSellerSignalsHeaderAdSlot, AuctionAdConfig.interestGroupBuyers, AuctionAdConfig.maxTrustedScoringSignalsURLLength, AuctionAdConfig.perBuyerCumulativeTimeouts, AuctionAdConfig.perBuyerCurrencies, AuctionAdConfig.perBuyerExperimentGroupIds, AuctionAdConfig.perBuyerGroupLimits, AuctionAdConfig.perBuyerMultiBidLimits, AuctionAdConfig.perBuyerPrioritySignals, AuctionAdConfig.perBuyerRealTimeReportingConfig, AuctionAdConfig.perBuyerSignals, AuctionAdConfig.perBuyerTimeouts, AuctionAdConfig.privateAggregationConfig, AuctionAdConfig.reportingTimeout, AuctionAdConfig.requestedSize, AuctionAdConfig.requestId, AuctionAdConfig.requiredSellerCapabilities, AuctionAdConfig.resolveToConfig, AuctionAdConfig.seller, AuctionAdConfig.sellerCurrency, AuctionAdConfig.sellerExperimentGroupId, AuctionAdConfig.sellerRealTimeReportingConfig, AuctionAdConfig.sellerSignals, AuctionAdConfig.sellerTimeout, AuctionAdConfig.sendCreativeScanningMetadata, AuctionAdConfig.serverResponse, AuctionAdConfig.signal, AuctionAdConfig.trustedScoringSignalsCoordinator, AuctionAdConfig.trustedScoringSignalsURL; see also WebIDLPedia
AuctionAdInterestGroup (WebIDL dictionary) §: Defined in Protected Audience; Related terms: AuctionAdInterestGroup.additionalBidKey, AuctionAdInterestGroup.lifetimeMs, AuctionAdInterestGroup.priority, AuctionAdInterestGroup.prioritySignalsOverrides, AuctionAdInterestGroup.privateAggregationConfig; see also WebIDLPedia
AuctionAdInterestGroupKey (WebIDL dictionary) §: Defined in Protected Audience; Related terms: AuctionAdInterestGroupKey.name, AuctionAdInterestGroupKey.owner; see also WebIDLPedia
AuctionAdInterestGroupSize (WebIDL dictionary) §: Defined in Protected Audience; Related terms: AuctionAdInterestGroupSize.height, AuctionAdInterestGroupSize.width; see also WebIDLPedia
AuctionAdConfig.auctionNonce (WebIDL dictionary member) §: Defined in Protected Audience
AuctionRealTimeReportingConfig (WebIDL dictionary) §: Defined in Protected Audience; Related terms: AuctionRealTimeReportingConfig.type; see also WebIDLPedia
AuctionReportBuyerDebugModeConfig (WebIDL dictionary) §: Defined in Protected Audience; Related terms: AuctionReportBuyerDebugModeConfig.debugKey, AuctionReportBuyerDebugModeConfig.enabled; see also WebIDLPedia
AuctionAdConfig.auctionReportBuyerDebugModeConfig (WebIDL dictionary member) §: Defined in Protected Audience
AuctionAdConfig.auctionReportBuyerKeys (WebIDL dictionary member) §: Defined in Protected Audience
AuctionAdConfig.auctionReportBuyers (WebIDL dictionary member) §: Defined in Protected Audience
AuctionReportBuyersConfig (WebIDL dictionary) §: Defined in Protected Audience; Related terms: AuctionReportBuyersConfig.bucket, AuctionReportBuyersConfig.scale; see also WebIDLPedia
AuctionAdConfig.auctionSignals (WebIDL dictionary member) §: Defined in Protected Audience
DirectFromSellerSignalsForBuyer.auctionSignals (WebIDL dictionary member) §: Defined in Protected Audience
DirectFromSellerSignalsForSeller.auctionSignals (WebIDL dictionary member) §: Defined in Protected Audience
"audio" (value for RequestDestination WebIDL enumeration) §: Defined in Fetch
audio (markup element) §: Defined in HTML; Referenced in Autoplay Policy Detection, CSS Cascading 5, CSS Display 3, CSS Display 4, Web Platform Design Principles, HTML Accessibility API Mappings 1.0, ARIA in HTML, Media Capture from DOM Elements, Media Capture and Streams, Mixed Content, Resource Timing, Selectors 4, Web Audio API, Web Audio API 1.1, Web MIDI API, WebVTT: The Web Video Text Tracks Format; Related terms: markup attribute autoplay, markup attribute controls, markup attribute crossorigin, markup attribute loop, markup attribute muted, markup attribute preload, markup attribute src
"audio" (value for ContentCategory WebIDL enumeration) §: Defined in Content Index
audio (markup element) §: Defined in EPUB 3.3 , EPUB 3.4
"audio" (value for OpusApplication WebIDL enumeration) §: Defined in Opus WebCodecs Registration
DisplayMediaStreamOptions.audio (WebIDL dictionary member) §: Defined in Screen Capture
MediaCapabilitiesKeySystemConfiguration.audio (WebIDL dictionary member) §: Defined in Media Capabilities
MediaConfiguration.audio (WebIDL dictionary member) §: Defined in Media Capabilities
MediaStreamConstraints.audio (WebIDL dictionary member) §: Defined in Media Capture and Streams
AudioPlayoutStats.[[audio context]] (internal slot) §: Defined in Playout Statistics API for WebAudio
audio or video MIME type (concept) §: Defined in MIME Sniffing; Referenced in HTML
audio or video type pattern matching algorithm (concept) §: Defined in MIME Sniffing
"audio-busy" (value for SpeechSynthesisErrorCode WebIDL enumeration) §: Defined in Web Speech API
audio-capture (concept) §: Defined in HTML
"audio-capture" (value for SpeechRecognitionErrorCode WebIDL enumeration) §: Defined in Web Speech API
"audio-hardware" (value for SpeechSynthesisErrorCode WebIDL enumeration) §: Defined in Web Speech API
MediaRecorder.audioBitrateMode (WebIDL attribute) §: Defined in MediaStream Recording
MediaRecorderOptions.audioBitrateMode (WebIDL dictionary member) §: Defined in MediaStream Recording
MediaRecorder.audioBitsPerSecond (WebIDL attribute) §: Defined in MediaStream Recording
MediaRecorderOptions.audioBitsPerSecond (WebIDL dictionary member) §: Defined in MediaStream Recording
AudioBuffer (WebIDL interface) §: Defined in Web Audio API , Web Audio API 1.1; Referenced in WebCodecs; Related terms: undefinedduration, undefined[[internal data]], undefined[[length]], undefined[[number of channels]], undefinednumberOfChannels, undefined[[sample rate]], undefinedsampleRate, undefinedAudioBuffer(options), undefinedcopyFromChannel(destination, channelNumber, bufferOffset), undefinedcopyToChannel(source, channelNumber, bufferOffset), undefinedgetChannelData(channel); see also WebIDLPedia
new AudioBuffer(options) (WebIDL constructor) §
new AudioBuffer(options) (WebIDL constructor) §: Defined in Web Audio API , Web Audio API 1.1
AudioBufferOptions (WebIDL dictionary) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefinedlength, undefinednumberOfChannels, undefinedsampleRate; see also WebIDLPedia
AudioBufferSourceNode (WebIDL interface) §: Defined in Web Audio API , Web Audio API 1.1; Referenced in Prerendering Revamped; Related terms: undefinedbuffer, undefined[[buffer set]], undefineddetune, undefinedloop, undefinedloopEnd, undefinedloopStart, undefinedplaybackRate, undefinedAudioBufferSourceNode(context, options), undefinedstart(when, offset, duration); see also WebIDLPedia
new AudioBufferSourceNode(context, options) (WebIDL constructor) §
new AudioBufferSourceNode(context, options) (WebIDL constructor) §: Defined in Web Audio API , Web Audio API 1.1
AudioBufferSourceOptions (WebIDL dictionary) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefinedbuffer, undefineddetune, undefinedloop, undefinedloopEnd, undefinedloopStart, undefinedplaybackRate; see also WebIDLPedia
MediaKeySystemConfiguration.audioCapabilities (WebIDL dictionary member) §: Defined in Encrypted Media Extensions; Referenced in Media Capabilities
AudioConfiguration (WebIDL dictionary) §: Defined in Media Capabilities; Related terms: AudioConfiguration.bitrate, AudioConfiguration.channels, AudioConfiguration.contentType, AudioConfiguration.samplerate, AudioConfiguration.spatialRendering; see also WebIDLPedia
"audiocontext" (value for AutoplayPolicyMediaType WebIDL enumeration) §: Defined in Autoplay Policy Detection
AudioContext (WebIDL interface) §: Defined in Web Audio API , Web Audio API 1.1; Referenced in Playout Statistics API for WebAudio, Prerendering Revamped, Audio Session, Autoplay Policy Detection; Related terms: undefinedbaseLatency, undefinedinterruption-end, undefinedinterruption-start, undefinedonerror, undefinedonsinkchange, undefinedoutputLatency, undefined[[pending resume promises]], AudioContext.[[playout stats]], AudioContext.playoutStats, undefined[[sink ID]], undefined[[sink ID at construction]], undefinedsinkId, undefined[[suspended by user]], undefinedAudioContext(contextOptions), event error, event sinkchange, undefinedclose(), undefinedcreateMediaElementSource(mediaElement), undefinedcreateMediaStreamDestination(), undefinedcreateMediaStreamSource(mediaStream), undefinedcreateMediaStreamTrackSource(mediaStreamTrack), undefinedgetOutputTimestamp(), undefinedresume(), undefinedsetSinkId((DOMString or AudioSinkOptions) sinkId), undefinedsetSinkId(sinkId), undefinedsuspend(); see also WebIDLPedia
new AudioContext(contextOptions) (WebIDL constructor) §
new AudioContext(contextOptions) (WebIDL constructor) §: Defined in Web Audio API , Web Audio API 1.1; Referenced in Prerendering Revamped
AudioContextLatencyCategory (WebIDL enumeration) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: value balanced, value interactive, value playback; see also WebIDLPedia
AudioContextOptions (WebIDL dictionary) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefinedlatencyHint, undefinedrenderSizeHint, undefinedsampleRate, undefinedsinkId; see also WebIDLPedia
AudioContextRenderSizeCategory (WebIDL enumeration) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: value default, value hardware; see also WebIDLPedia
AudioContextState (WebIDL enumeration) §: Defined in Web Audio API , Web Audio API 1.1; Referenced in Autoplay Policy Detection; Related terms: value closed, value interrupted, value running, value suspended; see also WebIDLPedia
AudioData (WebIDL interface) §: Defined in WebCodecs; Referenced in Linear PCM WebCodecs Registration; Related terms: AudioData.duration, undefined[[format]], AudioData.[[number of channels]], AudioData.[[number of frames]], AudioData.numberOfChannels, AudioData.numberOfFrames, AudioData.[[resource reference]], AudioData.[[sample rate]], AudioData.sampleRate, undefined[[timestamp]], new AudioData(init), AudioData.allocationSize(options), AudioData.clone(), AudioData.close(), AudioData.copyTo(destination, options); see also WebIDLPedia
new AudioData(init) (WebIDL constructor) §: Defined in WebCodecs
AudioDataCopyToOptions (WebIDL dictionary) §: Defined in WebCodecs; Related terms: AudioDataCopyToOptions.format, AudioDataCopyToOptions.frameCount, AudioDataCopyToOptions.frameOffset, AudioDataCopyToOptions.planeIndex; see also WebIDLPedia
AudioDataInit (WebIDL dictionary) §: Defined in WebCodecs; Related terms: AudioDataInit.data, AudioDataInit.format, AudioDataInit.numberOfChannels, AudioDataInit.numberOfFrames, AudioDataInit.sampleRate, AudioDataInit.timestamp, AudioDataInit.transfer; see also WebIDLPedia
AudioDataOutputCallback (WebIDL callback) §: Defined in WebCodecs
AudioDecoder (WebIDL interface) §: Defined in WebCodecs; Related terms: AudioDecoder.[[codec implementation]], AudioDecoder.[[codec saturated]], AudioDecoder.[[codec work queue]], AudioDecoder.[[control message queue]], undefined[[decodeQueueSize]], AudioDecoder.[[dequeue event scheduled]], AudioDecoder.[[error callback]], AudioDecoder.[[key chunk required]], AudioDecoder.[[message queue blocked]], AudioDecoder.ondequeue, AudioDecoder.[[output callback]], AudioDecoder.[[pending flush promises]], undefined[[state]], new AudioDecoder(init), event dequeue, AudioDecoder.close(), AudioDecoder.configure(config), AudioDecoder.decode(chunk), AudioDecoder.flush(), AudioDecoder.isConfigSupported(config), AudioDecoder.reset(); see also WebIDLPedia
new AudioDecoder(init) (WebIDL constructor) §: Defined in WebCodecs
AudioDecoderConfig (WebIDL dictionary) §: Defined in WebCodecs; Referenced in A-law PCM WebCodecs Registration, WebCodecs Codec Registry, Linear PCM WebCodecs Registration, u-law PCM WebCodecs Registration; Related terms: AudioDecoderConfig.codec, AudioDecoderConfig.description, AudioDecoderConfig.numberOfChannels, AudioDecoderConfig.sampleRate; see also WebIDLPedia
AudioDecoderInit (WebIDL dictionary) §: Defined in WebCodecs; Related terms: AudioDecoderInit.error, AudioDecoderInit.output; see also WebIDLPedia
AudioDecoderSupport (WebIDL dictionary) §: Defined in WebCodecs; Related terms: AudioDecoderSupport.config, AudioDecoderSupport.supported; see also WebIDLPedia
AudioDestinationNode (WebIDL interface) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefinedmaxChannelCount; see also WebIDLPedia
AudioEncoder (WebIDL interface) §: Defined in WebCodecs; Related terms: AudioEncoder.[[active encoder config]], AudioEncoder.[[active output config]], AudioEncoder.[[codec implementation]], AudioEncoder.[[codec saturated]], AudioEncoder.[[codec work queue]], AudioEncoder.[[control message queue]], AudioEncoder.[[dequeue event scheduled]], undefined[[encodeQueueSize]], AudioEncoder.[[error callback]], AudioEncoder.[[message queue blocked]], AudioEncoder.ondequeue, AudioEncoder.[[output callback]], AudioEncoder.[[pending flush promises]], undefined[[state]], new AudioEncoder(init), event dequeue, AudioEncoder.close(), AudioEncoder.configure(config), AudioEncoder.encode(data), AudioEncoder.flush(), AudioEncoder.isConfigSupported(config), AudioEncoder.reset(); see also WebIDLPedia
new AudioEncoder(init) (WebIDL constructor) §: Defined in WebCodecs
AudioEncoderConfig (WebIDL dictionary) §: Defined in WebCodecs; Referenced in AAC WebCodecs Registration, WebCodecs Codec Registry, FLAC WebCodecs Registration, Opus WebCodecs Registration; Related terms: AudioEncoderConfig.aac, AudioEncoderConfig.bitrate, AudioEncoderConfig.bitrateMode, AudioEncoderConfig.codec, AudioEncoderConfig.flac, AudioEncoderConfig.numberOfChannels, AudioEncoderConfig.opus, AudioEncoderConfig.sampleRate; see also WebIDLPedia
AudioEncoderInit (WebIDL dictionary) §: Defined in WebCodecs; Related terms: AudioEncoderInit.error, AudioEncoderInit.output; see also WebIDLPedia
AudioEncoderSupport (WebIDL dictionary) §: Defined in WebCodecs; Related terms: AudioEncoderSupport.config, AudioEncoderSupport.supported; see also WebIDLPedia
audioend (event for SpeechRecognition ) §: Defined in Web Speech API
"audioinput" (value for MediaDeviceKind WebIDL enumeration) §: Defined in Media Capture and Streams
RTCAudioSourceStats.audioLevel (WebIDL dictionary member) §: Defined in WebRTC Statistics
RTCEncodedAudioFrameMetadata.audioLevel (WebIDL dictionary member) §: Defined in WebRTC Encoded Transform
RTCInboundRtpStreamStats.audioLevel (WebIDL dictionary member) §: Defined in WebRTC Statistics
RTCRtpContributingSource.audioLevel (WebIDL dictionary member) §: Defined in WebRTC 1.0
AudioListener (WebIDL interface) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefinedforwardX, undefinedforwardY, undefinedforwardZ, undefinedpositionX, undefinedpositionY, undefinedpositionZ, undefinedupX, undefinedupY, undefinedupZ, undefinedsetOrientation(x, y, z, xUp, yUp, zUp), undefinedsetPosition(x, y, z); see also WebIDLPedia
AudioNode (WebIDL interface) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefinedchannelCount, undefinedchannelCountMode, undefinedchannelInterpretation, undefinedcontext, undefinednumberOfInputs, undefinednumberOfOutputs, undefinedconnect(destinationNode, output, input), undefinedconnect(destinationParam, output), undefineddisconnect(), undefineddisconnect(destinationNode, output, input), undefineddisconnect(destinationNode, output), undefineddisconnect(destinationNode), undefineddisconnect(destinationParam, output), undefineddisconnect(destinationParam), undefineddisconnect(output); see also WebIDLPedia
AudioNodeOptions (WebIDL dictionary) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefinedchannelCount, undefinedchannelCountMode, undefinedchannelInterpretation; see also WebIDLPedia
"audiooutput" (value for MediaDeviceKind WebIDL enumeration) §: Defined in Media Capture and Streams
AudioOutputOptions (WebIDL dictionary) §: Defined in Audio Output Devices API; Related terms: AudioOutputOptions.deviceId; see also WebIDLPedia
AudioParam (WebIDL interface) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefinedautomationRate, undefined[[current value]], undefineddefaultValue, undefinedmaxValue, undefinedminValue, undefinedvalue, undefinedcancelAndHoldAtTime(cancelTime), undefinedcancelScheduledValues(cancelTime), undefinedexponentialRampToValueAtTime(value, endTime), undefinedlinearRampToValueAtTime(value, endTime), undefinedsetTargetAtTime(target, startTime, timeConstant), undefinedsetValueAtTime(value, startTime), undefinedsetValueCurveAtTime(values, startTime, duration); see also WebIDLPedia
AudioParamDescriptor (WebIDL dictionary) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefinedautomationRate, undefineddefaultValue, undefinedmaxValue, undefinedminValue, undefinedname; see also WebIDLPedia
AudioParamMap (WebIDL interface) §: Defined in Web Audio API , Web Audio API 1.1; see also WebIDLPedia
AudioPlayoutStats (WebIDL interface) §: Defined in Playout Statistics API for WebAudio; Related terms: AudioPlayoutStats.[[audio context]], AudioPlayoutStats.[[average latency]], AudioPlayoutStats.averageLatency, AudioPlayoutStats.[[fallback frames duration]], AudioPlayoutStats.[[fallback frames events]], AudioPlayoutStats.fallbackFramesDuration, AudioPlayoutStats.fallbackFramesEvents, AudioPlayoutStats.[[latency reset time]], AudioPlayoutStats.[[maximum latency]], AudioPlayoutStats.maximumLatency, AudioPlayoutStats.[[minimum latency]], AudioPlayoutStats.minimumLatency, AudioPlayoutStats.[[total frames duration]], AudioPlayoutStats.totalFramesDuration, AudioPlayoutStats.resetLatency(); see also WebIDLPedia
audioprocess (event for ScriptProcessorNode ) §: Defined in Web Audio API , Web Audio API 1.1
AudioProcessingEvent (WebIDL interface) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefinedinputBuffer, undefinedoutputBuffer, undefinedplaybackTime, undefinedAudioProcessingEvent(type, eventInitDict); see also WebIDLPedia
new AudioProcessingEvent(type, eventInitDict) (WebIDL constructor) §
new AudioProcessingEvent(type, eventInitDict) (WebIDL constructor) §: Defined in Web Audio API , Web Audio API 1.1
AudioProcessingEventInit (WebIDL dictionary) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefinedinputBuffer, undefinedoutputBuffer, undefinedplaybackTime; see also WebIDLPedia
AudioSampleFormat (WebIDL enumeration) §: Defined in WebCodecs; Referenced in Linear PCM WebCodecs Registration; Related terms: value f32, value f32-planar, value s16, value s16-planar, value s32, value s32-planar, value u8, value u8-planar; see also WebIDLPedia
AudioScheduledSourceNode (WebIDL interface) §: Defined in Web Audio API , Web Audio API 1.1; Referenced in Prerendering Revamped; Related terms: undefinedonended, undefined[[source started]], event ended, undefinedstart(when), undefinedstop(when); see also WebIDLPedia
AudioSession (WebIDL interface) §: Defined in Audio Session; Related terms: AudioSession.onstatechange, AudioSession.state, AudioSession.type; see also WebIDLPedia
Navigator.audioSession (WebIDL attribute) §: Defined in Audio Session
AudioSessionState (WebIDL enumeration) §: Defined in Audio Session; Related terms: value active, value inactive, value interrupted; see also WebIDLPedia
AudioSessionType (WebIDL enumeration) §: Defined in Audio Session; Related terms: value ambient, value auto, value play-and-record, value playback, value transient, value transient-solo; see also WebIDLPedia
AudioSinkInfo (WebIDL interface) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefinedtype; see also WebIDLPedia
AudioSinkOptions (WebIDL dictionary) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefinedtype; see also WebIDLPedia
AudioSinkType (WebIDL enumeration) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: value none; see also WebIDLPedia
audiostart (event for SpeechRecognition ) §: Defined in Web Speech API
AudioTimestamp (WebIDL dictionary) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefinedcontextTime, undefinedperformanceTime; see also WebIDLPedia
AudioTrack (WebIDL interface) §: Defined in HTML; Referenced in Media Source Extensions™, Media Capture from DOM Elements, Media Capture and Streams, ISO BMFF Byte Stream Format, MPEG-2 TS Byte Stream Format, WebM Byte Stream Format; Related terms: AudioTrack.enabled, AudioTrack.id, AudioTrack.kind, AudioTrack.label, AudioTrack.language, AudioTrack.sourceBuffer; see also WebIDLPedia
AudioTrackList (WebIDL interface) §: Defined in HTML; Referenced in Media Source Extensions™, Media Capture and Streams; Related terms: AudioTrackList.length, undefinedonaddtrack, undefinedonchange, undefinedonremovetrack, event addtrack, event change, event removetrack, AudioTrackList.getTrackById(id); see also WebIDLPedia
HTMLMediaElement.audioTracks (WebIDL attribute) §: Defined in HTML; Referenced in Media Source Extensions™, Open Screen Application Protocol
SourceBuffer.audioTracks (WebIDL attribute) §: Defined in Media Source Extensions™
"audioworklet" (value for RequestDestination WebIDL enumeration) §: Defined in Fetch
BaseAudioContext.audioWorklet (WebIDL attribute) §
BaseAudioContext.audioWorklet (WebIDL attribute) §: Defined in Web Audio API , Web Audio API 1.1
AudioWorklet (WebIDL interface) §: Defined in Web Audio API , Web Audio API 1.1; Referenced in Web Platform Design Principles, Media Session, WebCodecs; Related terms: undefinedport; see also WebIDLPedia
AudioWorkletGlobalScope (WebIDL interface) §: Defined in Web Audio API , Web Audio API 1.1; Referenced in WebDriver BiDi; Related terms: undefinedcurrentFrame, undefinedcurrentTime, undefinedport, undefinedrenderQuantumSize, undefinedsampleRate, undefinedregisterProcessor(name, processorCtor); see also WebIDLPedia
AudioWorkletNode (WebIDL interface) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefinedonprocessorerror, undefinedparameters, undefinedport, undefinedAudioWorkletNode(context, name, options), event processorerror; see also WebIDLPedia
new AudioWorkletNode(context, name, options) (WebIDL constructor) §
new AudioWorkletNode(context, name, options) (WebIDL constructor) §: Defined in Web Audio API , Web Audio API 1.1
AudioWorkletNodeOptions (WebIDL dictionary) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefinednumberOfInputs, undefinednumberOfOutputs, undefinedoutputChannelCount, undefinedparameterData, undefinedprocessorOptions; see also WebIDLPedia
AudioWorkletProcessCallback (WebIDL callback) §: Defined in Web Audio API , Web Audio API 1.1
AudioWorkletProcessor (WebIDL interface) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefined[[callable process]], undefined[[node reference]], undefinedport, undefinedAudioWorkletProcessor(); see also WebIDLPedia
new AudioWorkletProcessor() (WebIDL constructor) §
new AudioWorkletProcessor() (WebIDL constructor) §: Defined in Web Audio API , Web Audio API 1.1
AudioWorkletProcessorConstructor (WebIDL callback) §: Defined in Web Audio API , Web Audio API 1.1
aural (CSS value for @media ) §: Defined in Media Queries 4 , Media Queries 5; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Speech 1, CSS 2
aural box model (concept) §: Defined in CSS Speech 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
"auth" (value for PushEncryptionKeyName WebIDL enumeration) §: Defined in Push API
BluetoothCharacteristicProperties.authenticatedSignedWrites (WebIDL attribute) §: Defined in Web Bluetooth
authentication (concept) §: Defined in Controlled Identifiers v1.0: A process by which an entity can prove to a verifier that it has a specific attribute or controls a specific secret.
"authentication" (value for SFrameTransformErrorEventType WebIDL enumeration) §: Defined in WebRTC Encoded Transform
authentication entry (concept) §: Defined in Fetch; Referenced in Clear Site Data
AuthenticationExtensionsClientInputs (WebIDL dictionary) §: Defined in Web Authentication; Referenced in CTAP, Secure Payment Confirmation; Related terms: AuthenticationExtensionsClientInputs.appid, AuthenticationExtensionsClientInputs.appidExclude, AuthenticationExtensionsClientInputs.credBlob, AuthenticationExtensionsClientInputs.credentialProtectionPolicy, AuthenticationExtensionsClientInputs.credProps, AuthenticationExtensionsClientInputs.enforceCredentialProtectionPolicy, AuthenticationExtensionsClientInputs.getCredBlob, AuthenticationExtensionsClientInputs.hmacCreateSecret, AuthenticationExtensionsClientInputs.hmacGetSecret, AuthenticationExtensionsClientInputs.largeBlob, AuthenticationExtensionsClientInputs.minPinLength, AuthenticationExtensionsClientInputs.payment, AuthenticationExtensionsClientInputs.prf; see also WebIDLPedia
AuthenticationExtensionsClientInputsJSON (WebIDL dictionary) §: Defined in Web Authentication; Related terms: AuthenticationExtensionsClientInputsJSON.appid, AuthenticationExtensionsClientInputsJSON.appidExclude, AuthenticationExtensionsClientInputsJSON.credProps, AuthenticationExtensionsClientInputsJSON.largeBlob, AuthenticationExtensionsClientInputsJSON.prf; see also WebIDLPedia
AuthenticationExtensionsClientOutputs (WebIDL dictionary) §: Defined in Web Authentication; Referenced in CTAP, Secure Payment Confirmation; Related terms: AuthenticationExtensionsClientOutputs.appid, AuthenticationExtensionsClientOutputs.appidExclude, AuthenticationExtensionsClientOutputs.credProps, AuthenticationExtensionsClientOutputs.hmacCreateSecret, AuthenticationExtensionsClientOutputs.hmacGetSecret, AuthenticationExtensionsClientOutputs.largeBlob, AuthenticationExtensionsClientOutputs.payment, AuthenticationExtensionsClientOutputs.prf; see also WebIDLPedia
AuthenticationExtensionsClientOutputsJSON (WebIDL dictionary) §: Defined in Web Authentication; Related terms: AuthenticationExtensionsClientOutputsJSON.appid, AuthenticationExtensionsClientOutputsJSON.appidExclude, AuthenticationExtensionsClientOutputsJSON.credProps, AuthenticationExtensionsClientOutputsJSON.largeBlob, AuthenticationExtensionsClientOutputsJSON.prf; see also WebIDLPedia
AuthenticationExtensionsLargeBlobInputs (WebIDL dictionary) §: Defined in Web Authentication; Related terms: AuthenticationExtensionsLargeBlobInputs.read, AuthenticationExtensionsLargeBlobInputs.support, AuthenticationExtensionsLargeBlobInputs.write; see also WebIDLPedia
AuthenticationExtensionsLargeBlobInputsJSON (WebIDL dictionary) §: Defined in Web Authentication; Related terms: AuthenticationExtensionsLargeBlobInputsJSON.read, AuthenticationExtensionsLargeBlobInputsJSON.support, AuthenticationExtensionsLargeBlobInputsJSON.write; see also WebIDLPedia
AuthenticationExtensionsLargeBlobOutputs (WebIDL dictionary) §: Defined in Web Authentication; Related terms: AuthenticationExtensionsLargeBlobOutputs.blob, AuthenticationExtensionsLargeBlobOutputs.supported, AuthenticationExtensionsLargeBlobOutputs.written; see also WebIDLPedia
AuthenticationExtensionsLargeBlobOutputsJSON (WebIDL dictionary) §: Defined in Web Authentication; Related terms: AuthenticationExtensionsLargeBlobOutputsJSON.blob, AuthenticationExtensionsLargeBlobOutputsJSON.supported, AuthenticationExtensionsLargeBlobOutputsJSON.written; see also WebIDLPedia
AuthenticationExtensionsPaymentInputs (WebIDL dictionary) §: Defined in Secure Payment Confirmation; Related terms: AuthenticationExtensionsPaymentInputs.browserBoundPubKeyCredParams, AuthenticationExtensionsPaymentInputs.instrument, AuthenticationExtensionsPaymentInputs.isPayment, AuthenticationExtensionsPaymentInputs.payeeName, AuthenticationExtensionsPaymentInputs.payeeOrigin, AuthenticationExtensionsPaymentInputs.paymentEntitiesLogos, AuthenticationExtensionsPaymentInputs.rpId, AuthenticationExtensionsPaymentInputs.topOrigin, AuthenticationExtensionsPaymentInputs.total; see also WebIDLPedia
AuthenticationExtensionsPaymentOutputs (WebIDL dictionary) §: Defined in Secure Payment Confirmation; Related terms: AuthenticationExtensionsPaymentOutputs.browserBoundSignature; see also WebIDLPedia
AuthenticationExtensionsPRFInputs (WebIDL dictionary) §: Defined in Web Authentication; Related terms: AuthenticationExtensionsPRFInputs.eval, AuthenticationExtensionsPRFInputs.evalByCredential; see also WebIDLPedia
AuthenticationExtensionsPRFInputsJSON (WebIDL dictionary) §: Defined in Web Authentication; Related terms: AuthenticationExtensionsPRFInputsJSON.eval, AuthenticationExtensionsPRFInputsJSON.evalByCredential; see also WebIDLPedia
AuthenticationExtensionsPRFOutputs (WebIDL dictionary) §: Defined in Web Authentication; Related terms: AuthenticationExtensionsPRFOutputs.enabled, AuthenticationExtensionsPRFOutputs.results; see also WebIDLPedia
AuthenticationExtensionsPRFOutputsJSON (WebIDL dictionary) §: Defined in Web Authentication; Related terms: AuthenticationExtensionsPRFOutputsJSON.enabled, AuthenticationExtensionsPRFOutputsJSON.results; see also WebIDLPedia
AuthenticationExtensionsPRFValues (WebIDL dictionary) §: Defined in Web Authentication; Related terms: AuthenticationExtensionsPRFValues.first, AuthenticationExtensionsPRFValues.second; see also WebIDLPedia
AuthenticationExtensionsPRFValuesJSON (WebIDL dictionary) §: Defined in Web Authentication; Related terms: AuthenticationExtensionsPRFValuesJSON.first, AuthenticationExtensionsPRFValuesJSON.second; see also WebIDLPedia
AuthenticationResponseJSON (WebIDL dictionary) §: Defined in Web Authentication; Related terms: AuthenticationResponseJSON.authenticatorAttachment, AuthenticationResponseJSON.clientExtensionResults, AuthenticationResponseJSON.id, AuthenticationResponseJSON.rawId, AuthenticationResponseJSON.response, AuthenticationResponseJSON.type; see also WebIDLPedia
AuthenticatorAssertionResponse (WebIDL interface) §: Defined in Web Authentication; Related terms: AuthenticatorAssertionResponse.authenticatorData, AuthenticatorAssertionResponse.signature, AuthenticatorAssertionResponse.userHandle; see also WebIDLPedia
AuthenticatorAssertionResponseJSON (WebIDL dictionary) §: Defined in Web Authentication; Related terms: AuthenticatorAssertionResponseJSON.authenticatorData, AuthenticatorAssertionResponseJSON.clientDataJSON, AuthenticatorAssertionResponseJSON.signature, AuthenticatorAssertionResponseJSON.userHandle; see also WebIDLPedia
AuthenticationResponseJSON.authenticatorAttachment (WebIDL dictionary member) §: Defined in Web Authentication
AuthenticatorSelectionCriteria.authenticatorAttachment (WebIDL dictionary member) §: Defined in Web Authentication; Referenced in Secure Payment Confirmation
PublicKeyCredential.authenticatorAttachment (WebIDL attribute) §: Defined in Web Authentication
RegistrationResponseJSON.authenticatorAttachment (WebIDL dictionary member) §: Defined in Web Authentication
AuthenticatorAttachment (WebIDL enumeration) §: Defined in Web Authentication; Related terms: value cross-platform, value platform; see also WebIDLPedia
AuthenticatorAttestationResponse (WebIDL interface) §: Defined in Web Authentication; Related terms: AuthenticatorAttestationResponse.attestationObject, AuthenticatorAttestationResponse.[[transports]], AuthenticatorAttestationResponse.getAuthenticatorData(), AuthenticatorAttestationResponse.getPublicKey(), AuthenticatorAttestationResponse.getPublicKeyAlgorithm(), AuthenticatorAttestationResponse.getTransports(); see also WebIDLPedia
AuthenticatorAttestationResponseJSON (WebIDL dictionary) §: Defined in Web Authentication; Related terms: AuthenticatorAttestationResponseJSON.attestationObject, AuthenticatorAttestationResponseJSON.authenticatorData, AuthenticatorAttestationResponseJSON.clientDataJSON, AuthenticatorAttestationResponseJSON.publicKey, AuthenticatorAttestationResponseJSON.publicKeyAlgorithm, AuthenticatorAttestationResponseJSON.transports; see also WebIDLPedia
AuthenticatorAssertionResponse.authenticatorData (WebIDL attribute) §: Defined in Web Authentication
AuthenticatorAssertionResponseJSON.authenticatorData (WebIDL dictionary member) §: Defined in Web Authentication
AuthenticatorAttestationResponseJSON.authenticatorData (WebIDL dictionary member) §: Defined in Web Authentication
AuthenticatorResponse (WebIDL interface) §: Defined in Web Authentication; Related terms: AuthenticatorResponse.clientDataJSON; see also WebIDLPedia
PublicKeyCredentialCreationOptions.authenticatorSelection (WebIDL dictionary member) §: Defined in Web Authentication; Referenced in CTAP, Secure Payment Confirmation
PublicKeyCredentialCreationOptionsJSON.authenticatorSelection (WebIDL dictionary member) §: Defined in Web Authentication
AuthenticatorSelectionCriteria (WebIDL dictionary) §: Defined in Web Authentication; Related terms: AuthenticatorSelectionCriteria.authenticatorAttachment, AuthenticatorSelectionCriteria.requireResidentKey, AuthenticatorSelectionCriteria.residentKey, AuthenticatorSelectionCriteria.userVerification; see also WebIDLPedia
AuthenticatorTransport (WebIDL enumeration) §: Defined in Web Authentication; Related terms: value ble, value hybrid, value internal, value nfc, value smart-card, value usb; see also WebIDLPedia
author (value for name attribute of meta element ) §: Defined in HTML
author (value for rel attribute of a, rel attribute of area element, rel attribute of link element ) §: Defined in HTML
Author (concept) §: Defined in CSS Snapshot 2022 , CSS Snapshot 2023 , CSS Snapshot 2024 , CSS Snapshot 2025
author origin (concept) §: Defined in CSS Cascading 3 , CSS Cascading 4 , CSS Cascading 5; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Anchor Positioning, CSS Cascading 6, CSS Color Adjustment 1, CSS Lists 3, CSS Pseudo-Elements 4, CSS Text 4, CSS User Interface 4
authoring tool (concept) §: Defined in CSS Snapshot 2022 , CSS Snapshot 2023 , CSS Snapshot 2024 , CSS Snapshot 2025
authority (concept for state of constructor string parser ) §: Defined in URL Pattern
authority state (concept for basic URL parser ) §: Defined in URL
authorization (concept) §: Defined in Controlled Identifiers v1.0: A process by which an entity can prove to a verifier that it is allowed to perform a specific activity.
auto (CSS value for background-size ) §: Defined in CSS Backgrounds 4 , CSS Backgrounds 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for shape-inside ) §: Defined in CSS Shapes 2
auto (CSS value for text-size-adjust ) §: Defined in CSS Size Adjustment 1
"auto" (value for RequestPriority WebIDL enumeration) §: Defined in Fetch
"auto" (value for FullscreenNavigationUI WebIDL enumeration) §: Defined in Fullscreen API
auto (value for fetchpriority attribute of img element, fetchpriority attribute of link element, fetchpriority attribute of script ) §: Defined in HTML
auto (value for dir attribute of html-global ) §: Defined in HTML
auto (value for decoding attribute of img element ) §: Defined in HTML
auto (value for preload attribute of audio element, preload attribute of video element ) §: Defined in HTML
"auto" (value for CanvasFontKerning WebIDL enumeration) §: Defined in HTML
"auto" (value for CanvasTextRendering WebIDL enumeration) §: Defined in HTML
auto (value for popover attribute of html-global ) §: Defined in HTML
"auto" (value for ScrollRestoration WebIDL enumeration) §: Defined in HTML
"auto" (value for NavigationHistoryBehavior WebIDL enumeration) §: Defined in HTML
"auto" (value for NotificationDirection WebIDL enumeration) §: Defined in Notifications API
"auto" (value for AudioSessionType WebIDL enumeration) §: Defined in Audio Session
auto (CSS value for justify-self ) §: Defined in CSS Box Alignment 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for align-self ) §: Defined in CSS Box Alignment 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Cascading 3, CSS Cascading 4, CSS Cascading 5
auto (CSS value for position-anchor ) §: Defined in CSS Anchor Positioning
auto (CSS value for animation-duration ) §: Defined in CSS Animations 2; Referenced in Scroll-driven Animations
auto (CSS value for <single-animation-timeline>, animation-timeline property ) §: Defined in CSS Animations 2; Referenced in CSS Values 5
auto (CSS value for timeline-trigger-exit-range, timeline-trigger-exit-range-end property, timeline-trigger-exit-range-start property ) §: Defined in CSS Animations 2
auto (CSS value for border-image-width ) §: Defined in CSS Backgrounds 3 , CSS Borders and Box Decorations 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for break-after, break-before property ) §: Defined in CSS Fragmentation 3 , CSS Fragmentation 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Regions 1
auto (CSS value for break-inside, page-break-inside property ) §: Defined in CSS Fragmentation 3 , CSS Fragmentation 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for margin-break ) §: Defined in CSS Fragmentation 4
auto (CSS value for forced-color-adjust ) §: Defined in CSS Color Adjustment 1
auto (CSS value for content-visibility ) §: Defined in CSS Containment 2
auto (CSS value for quotes ) §: Defined in CSS Generated Content 3
auto (CSS value for range descriptor of @counter-style @rule ) §: Defined in CSS Counter Styles 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for speak-as descriptor of @counter-style @rule ) §: Defined in CSS Counter Styles 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for flex-basis ) §: Defined in CSS Flexbox 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for align-items, align-self property ) §: Defined in CSS Flexbox 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for font-synthesis-weight ) §: Defined in CSS Fonts 4; Referenced in CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for font-synthesis-style ) §: Defined in CSS Fonts 4; Referenced in CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for font-synthesis-small-caps ) §: Defined in CSS Fonts 4; Referenced in CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for font-synthesis-position ) §: Defined in CSS Fonts 4; Referenced in CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for font-display descriptor of @font-face @rule ) §: Defined in CSS Fonts 4; Referenced in CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for font-kerning ) §: Defined in CSS Fonts 4; Referenced in CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for font-optical-sizing ) §: Defined in CSS Fonts 4; Referenced in CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for font-size descriptor of @font-face @rule ) §: Defined in CSS Fonts 5
auto (CSS value for slider-orientation ) §: Defined in CSS Form Control Styling 1
auto (CSS value for input-security ) §: Defined in CSS Form Control Styling 1
auto (CSS value for footnote-policy ) §: Defined in CSS GCPM 3
auto (CSS value for grid-template-columns, grid-template-rows property ) §: Defined in CSS Grid Layout 1 , CSS Grid Layout 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Grid Layout 3
auto (CSS value for <grid-line> ) §: Defined in CSS Grid Layout 1 , CSS Grid Layout 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for item-direction, item-track property ) §: Defined in CSS Grid Layout 3
auto (CSS value for item-cross, item-wrap property ) §: Defined in CSS Grid Layout 3
auto (CSS value for image-rendering ) §: Defined in CSS Images 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for dominant-baseline ) §: Defined in CSS Inline Layout 3
auto (CSS value for baseline-source, vertical-align property ) §: Defined in CSS Inline Layout 3; Referenced in CSS Box Alignment 3
auto (CSS value for text-box-edge ) §: Defined in CSS Inline Layout 3
auto (CSS value for column-width ) §: Defined in CSS Multicol 1 , CSS Multicol 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Box Alignment 3, CSS Writing Modes 4
auto (CSS value for column-count ) §: Defined in CSS Multicol 1 , CSS Multicol 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Writing Modes 4
auto (CSS value for column-fill ) §: Defined in CSS Multicol 1 , CSS Multicol 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for column-height ) §: Defined in CSS Multicol 2
auto (CSS value for column-wrap ) §: Defined in CSS Multicol 2
auto (CSS value for column-span ) §: Defined in CSS Multicol 2
auto (CSS value for spatial-navigation-contain ) §: Defined in CSS Spatial Navigation 1
auto (CSS value for spatial-navigation-action ) §: Defined in CSS Spatial Navigation 1
auto (CSS value for overflow, overflow-x property, overflow-y property ) §: Defined in CSS Overflow 3 , CSS 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2025, CSS Fragmentation 3, CSS Fragmentation 4, CSS Overflow 4, CSS Transforms 1, CSS Values 3, CSSOM View
auto (CSS value for scroll-behavior ) §: Defined in CSS Overflow 3; Referenced in CSSOM View
auto (CSS value for scrollbar-gutter ) §: Defined in CSS Overflow 3; Referenced in CSS Overflow 4
auto (CSS value for block-ellipsis ) §: Defined in CSS Overflow 4
auto (CSS value for continue ) §: Defined in CSS Overflow 4; Referenced in CSS Overflow 5
auto (CSS value for scroll-target-group ) §: Defined in CSS Overflow 5
auto (CSS value for overscroll-behavior, overscroll-behavior-block property, overscroll-behavior-inline property, overscroll-behavior-x property, overscroll-behavior-y property ) §: Defined in CSS Overscroll Behavior 1
auto (CSS value for size descriptor of @page @rule ) §: Defined in CSS Paged Media 3
auto (CSS value for bleed descriptor of @page @rule ) §: Defined in CSS Paged Media 3
auto (CSS value for bottom, inset property, inset-block property, inset-block-end property, inset-block-start property, inset-inline property, inset-inline-end property, inset-inline-start property, left property, right property, top property ) §: Defined in CSS Positioned Layout 3 , CSS 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2025, CSS Box Alignment 3, CSS Anchor Positioning, CSS Typed OM 1
auto (CSS value for overlay ) §: Defined in CSS Positioned Layout 4
auto (CSS value for block-step-align ) §: Defined in CSS Rhythmic Sizing
auto (CSS value for viewport-fit ) §: Defined in CSS Round Display 1
auto (CSS value for ruby-merge ) §: Defined in CSS Ruby Annotation Layout 1
auto (CSS value for ruby-overhang ) §: Defined in CSS Ruby Annotation Layout 1
auto (CSS value for overflow-anchor ) §: Defined in CSS Scroll Anchoring 1
auto (CSS value for scroll-padding, scroll-padding-block property, scroll-padding-block-end property, scroll-padding-block-start property, scroll-padding-inline property, scroll-padding-inline-end property, scroll-padding-inline-start property ) §: Defined in CSS Scroll Snap 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for scrollbar-color ) §: Defined in CSS Scrollbars Styling 1; Referenced in CSS Color Adjustment 1
auto (CSS value for scrollbar-width ) §: Defined in CSS Scrollbars Styling 1
auto (CSS value for height, min-height property, min-width property, width ) §: Defined in CSS Sizing 3 , CSS 2; Referenced in CSS Size Adjustment 1, Quirks Mode, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2025, CSS Box Alignment 3, CSS Fragmentation 3, CSS Fragmentation 4, CSS Flexbox 1, CSS Inline Layout 3, CSS Layout API 1, CSS Paged Media 3, CSS Positioned Layout 3, CSS Regions 1, CSS Sizing 4, CSS Values 3, CSS Values 4, CSS Values 5, CSS Writing Modes 3, CSS Writing Modes 4, WebVTT: The Web Video Text Tracks Format
auto (CSS value for aspect-ratio ) §: Defined in CSS Sizing 4
auto (CSS value for contain-intrinsic-block-size, contain-intrinsic-height property, contain-intrinsic-inline-size property, contain-intrinsic-size property, contain-intrinsic-width property ) §: Defined in CSS Sizing 4; Referenced in CSS Sizing 3
auto (CSS value for speak ) §: Defined in CSS Speech 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for voice-duration ) §: Defined in CSS Speech 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for line-break ) §: Defined in CSS Text 3 , CSS Text 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for hyphens ) §: Defined in CSS Text 3 , CSS Text 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for text-align-last ) §: Defined in CSS Text 3 , CSS Text 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for text-justify ) §: Defined in CSS Text 3 , CSS Text 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for wrap-inside ) §: Defined in CSS Text 4
auto (CSS value for wrap-after, wrap-before property ) §: Defined in CSS Text 4
auto (CSS value for text-wrap-style ) §: Defined in CSS Text 4
auto (CSS value for hyphenate-character ) §: Defined in CSS Text 4
auto (CSS value for hyphenate-limit-chars ) §: Defined in CSS Text 4
auto (CSS value for text-autospace ) §: Defined in CSS Text 4
auto (CSS value for text-spacing-trim ) §: Defined in CSS Text 4
auto (CSS value for text-spacing ) §: Defined in CSS Text 4
auto (CSS value for text-underline-position ) §: Defined in CSS Text Decoration 3 , CSS Text Decoration 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for text-decoration-thickness ) §: Defined in CSS Text Decoration 4
auto (CSS value for text-underline-offset ) §: Defined in CSS Text Decoration 4
auto (CSS value for text-decoration-skip-inset ) §: Defined in CSS Text Decoration 4
auto (CSS value for text-decoration-skip ) §: Defined in CSS Text Decoration 4
auto (CSS value for text-decoration-skip-self ) §: Defined in CSS Text Decoration 4
auto (CSS value for text-decoration-skip-ink ) §: Defined in CSS Text Decoration 4
auto (CSS value for cursor ) §: Defined in CSS User Interface 3 , CSS User Interface 4 , CSS 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for caret-color ) §: Defined in CSS User Interface 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS User Interface 4
auto (CSS value for outline-color ) §: Defined in CSS User Interface 4
auto (CSS value for caret-animation ) §: Defined in CSS User Interface 4
auto (CSS value for caret-shape ) §: Defined in CSS User Interface 4
auto (CSS value for user-select ) §: Defined in CSS User Interface 4
auto (CSS value for pointer-events ) §: Defined in CSS User Interface 4
auto (CSS value for interactivity ) §: Defined in CSS User Interface 4
auto (CSS value for accent-color ) §: Defined in CSS User Interface 4; Referenced in CSS Color Adjustment 1
auto (CSS value for appearance ) §: Defined in CSS User Interface 4
auto (CSS value for <random-value-sharing>, random() function ) §: Defined in CSS Values 5
auto (CSS value for navigation descriptor of @view-transition @rule ) §: Defined in CSS View Transitions 2
auto (concept for view-transition-name ) §: Defined in CSS View Transitions 2
auto (CSS value for will-change ) §: Defined in CSS Will Change 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
auto (CSS value for z-index ) §: Defined in CSS 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2025, CSS Color 4, CSS Flexbox 1, CSS Grid Layout 1, CSS Grid Layout 2, CSS Layout API 1, CSS Positioned Layout 3, CSS Transforms 1
auto (CSS value for width ) §: Defined in CSS 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2025
auto (CSS value for clip ) §: Defined in CSS 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2025, CSS Masking 1, CSS Transforms 2
auto (CSS value for <bottom>, <left> type, <right> type, <top> type ) §: Defined in CSS 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2025
auto (CSS value for page-break-after, page-break-before property, page-break-inside property ) §: Defined in CSS 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2025
auto (CSS value for table-layout ) §: Defined in CSS 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2025, CSS Flexbox 1
auto (CSS value for wrap-flow ) §: Defined in CSS Exclusions 1
"auto" (value for ScrollBehavior WebIDL enumeration) §: Defined in CSSOM View
auto (CSS value for color-interpolation-filters ) §: Defined in Filter Effects 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
"auto" (value for FillLightMode WebIDL enumeration) §: Defined in MediaStream Image Capture
"auto" (value for TextDirection WebIDL enumeration) §: Defined in MiniApp Lifecycle
auto (CSS value for offset-position ) §: Defined in Motion Path 1
auto (CSS value for offset-anchor ) §: Defined in Motion Path 1
auto (CSS value for offset-rotate ) §: Defined in Motion Path 1
auto (CSS value for view-timeline-inset ) §: Defined in Scroll-driven Animations
"auto" (value for FillMode, PlaybackDirection enumeration WebIDL enumerations) §: Defined in Web Animations , Web Animations 2
"auto" (value for CompositeOperationOrAuto WebIDL enumeration) §: Defined in Web Animations
"auto" (value for OpusSignal WebIDL enumeration) §: Defined in Opus WebCodecs Registration
"auto" (value for GPUAutoLayoutMode WebIDL enumeration) §: Defined in WebGPU
"auto" (value for AutoKeyword WebIDL enumeration) §: Defined in WebVTT: The Web Video Text Tracks Format
"auto" (value for PositionAlignSetting WebIDL enumeration) §: Defined in WebVTT: The Web Video Text Tracks Format
auto && <ratio> (CSS value for aspect-ratio ) §: Defined in CSS Sizing 4
auto direction (concept) §: Defined in Internationalization Glossary
auto-aligned start time (concept for animation ) §: Defined in Web Animations 2
auto-areas (CSS value for repeat() ) §: Defined in CSS Grid Layout 3
auto-fill (CSS value for repeat() ) §: Defined in CSS Grid Layout 1 , CSS Grid Layout 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Grid Layout 3
auto-fit (CSS value for repeat() ) §: Defined in CSS Grid Layout 1 , CSS Grid Layout 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Grid Layout 3
<auto-line-color-list> (CSS type) §: Defined in CSS Gap Decorations 1
<auto-line-style-list> (CSS type) §: Defined in CSS Gap Decorations 1
<auto-line-width-list> (CSS type) §: Defined in CSS Gap Decorations 1
auto-phrase (CSS value for word-space-transform ) §: Defined in CSS Text 4
auto-phrase (CSS value for word-break ) §: Defined in CSS Text 4
auto-placement cursor (concept) §: Defined in CSS Grid Layout 1 , CSS Grid Layout 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
<auto-repeat> (CSS type) §: Defined in CSS Grid Layout 1 , CSS Grid Layout 2; Related terms: CSS function repeat()
<auto-repeat-line-color> (CSS type) §: Defined in CSS Gap Decorations 1; Related terms: CSS function repeat()
<auto-repeat-line-style> (CSS type) §: Defined in CSS Gap Decorations 1; Related terms: CSS function repeat()
<auto-repeat-line-width> (CSS type) §: Defined in CSS Gap Decorations 1; Related terms: CSS function repeat()
<auto-track-list> (CSS type) §: Defined in CSS Grid Layout 1 , CSS Grid Layout 2
UnderlyingSource.autoAllocateChunkSize (WebIDL dictionary member) §: Defined in Streams
FragmentResultOptions.autoBlockSize (WebIDL dictionary member) §: Defined in CSS Layout API 1
autocapitalize (markup attribute for html-global ) §: Defined in HTML; Referenced in HTML Accessibility API Mappings 1.0; Related terms: value characters, value none, value off, value on, value sentences, value words
HTMLElement.autocapitalize (WebIDL attribute) §: Defined in HTML
autocomplete (markup attribute for form ) §: Defined in HTML; Referenced in HTML Accessibility API Mappings 1.0; Related terms: value off, value on
autocomplete (markup attribute for button, fieldset element, input element, object element, output element, select element, textarea element ) §: Defined in HTML; Referenced in HTML Accessibility API Mappings 1.0, Web Authentication; Related terms: value additional-name, value additional-name, value additional-name, value additional-name, value additional-name, value additional-name, value additional-name, value address-level1, value address-level1, value address-level1, value address-level1, value address-level1, value address-level1, value address-level1, value address-level2, value address-level2, value address-level2, value address-level2, value address-level2, value address-level2, value address-level2, value address-level3, value address-level3, value address-level3, value address-level3, value address-level3, value address-level3, value address-level3, value address-level4, value address-level4, value address-level4, value address-level4, value address-level4, value address-level4, value address-level4, value address-line1, value address-line1, value address-line1, value address-line1, value address-line1, value address-line1, value address-line1, value address-line2, value address-line2, value address-line2, value address-line2, value address-line2, value address-line2, value address-line2, value address-line3, value address-line3, value address-line3, value address-line3, value address-line3, value address-line3, value address-line3, value bday, value bday, value bday, value bday, value bday, value bday, value bday, value bday-day, value bday-day, value bday-day, value bday-day, value bday-day, value bday-day, value bday-day, value bday-month, value bday-month, value bday-month, value bday-month, value bday-month, value bday-month, value bday-month, value bday-year, value bday-year, value bday-year, value bday-year, value bday-year, value bday-year, value bday-year, value billing, value billing, value billing, value billing, value billing, value billing, value billing, value cc-additional-name, value cc-additional-name, value cc-additional-name, value cc-additional-name, value cc-additional-name, value cc-additional-name, value cc-additional-name, value cc-csc, value cc-csc, value cc-csc, value cc-csc, value cc-csc, value cc-csc, value cc-csc, value cc-exp, value cc-exp, value cc-exp, value cc-exp, value cc-exp, value cc-exp, value cc-exp, value cc-exp-month, value cc-exp-month, value cc-exp-month, value cc-exp-month, value cc-exp-month, value cc-exp-month, value cc-exp-month, value cc-exp-year, value cc-exp-year, value cc-exp-year, value cc-exp-year, value cc-exp-year, value cc-exp-year, value cc-exp-year, value cc-family-name, value cc-family-name, value cc-family-name, value cc-family-name, value cc-family-name, value cc-family-name, value cc-family-name, value cc-given-name, value cc-given-name, value cc-given-name, value cc-given-name, value cc-given-name, value cc-given-name, value cc-given-name, value cc-name, value cc-name, value cc-name, value cc-name, value cc-name, value cc-name, value cc-name, value cc-number, value cc-number, value cc-number, value cc-number, value cc-number, value cc-number, value cc-number, value cc-type, value cc-type, value cc-type, value cc-type, value cc-type, value cc-type, value cc-type, value country, value country, value country, value country, value country, value country, value country, value country-name, value country-name, value country-name, value country-name, value country-name, value country-name, value country-name, value current-password, value current-password, value current-password, value current-password, value current-password, value current-password, value current-password, value email, value email, value email, value email, value email, value email, value email, value family-name, value family-name, value family-name, value family-name, value family-name, value family-name, value family-name, value fax, value fax, value fax, value fax, value fax, value fax, value fax, value given-name, value given-name, value given-name, value given-name, value given-name, value given-name, value given-name, value home, value home, value home, value home, value home, value home, value home, value honorific-prefix, value honorific-prefix, value honorific-prefix, value honorific-prefix, value honorific-prefix, value honorific-prefix, value honorific-prefix, value honorific-suffix, value honorific-suffix, value honorific-suffix, value honorific-suffix, value honorific-suffix, value honorific-suffix, value honorific-suffix, value impp, value impp, value impp, value impp, value impp, value impp, value impp, value language, value language, value language, value language, value language, value language, value language, value mobile, value mobile, value mobile, value mobile, value mobile, value mobile, value mobile, value name, value name, value name, value name, value name, value name, value name, value new-password, value new-password, value new-password, value new-password, value new-password, value new-password, value new-password, value nickname, value nickname, value nickname, value nickname, value nickname, value nickname, value nickname, value off, value off, value off, value off, value off, value off, value off, value on, value on, value on, value on, value on, value on, value on, value one-time-code, value one-time-code, value one-time-code, value one-time-code, value one-time-code, value one-time-code, value one-time-code, value organization, value organization, value organization, value organization, value organization, value organization, value organization, value organization-title, value organization-title, value organization-title, value organization-title, value organization-title, value organization-title, value organization-title, value pager, value pager, value pager, value pager, value pager, value pager, value pager, value photo, value photo, value photo, value photo, value photo, value photo, value photo, value postal-code, value postal-code, value postal-code, value postal-code, value postal-code, value postal-code, value postal-code, value section-, value section-, value section-, value section-, value section-, value section-, value section-, value sex, value sex, value sex, value sex, value sex, value sex, value sex, value shipping, value shipping, value shipping, value shipping, value shipping, value shipping, value shipping, value street-address, value street-address, value street-address, value street-address, value street-address, value street-address, value street-address, value tel, value tel, value tel, value tel, value tel, value tel, value tel, value tel-area-code, value tel-area-code, value tel-area-code, value tel-area-code, value tel-area-code, value tel-area-code, value tel-area-code, value tel-country-code, value tel-country-code, value tel-country-code, value tel-country-code, value tel-country-code, value tel-country-code, value tel-country-code, value tel-extension, value tel-extension, value tel-extension, value tel-extension, value tel-extension, value tel-extension, value tel-extension, value tel-local, value tel-local, value tel-local, value tel-local, value tel-local, value tel-local, value tel-local, value tel-local-prefix, value tel-local-prefix, value tel-local-prefix, value tel-local-prefix, value tel-local-prefix, value tel-local-prefix, value tel-local-prefix, value tel-local-suffix, value tel-local-suffix, value tel-local-suffix, value tel-local-suffix, value tel-local-suffix, value tel-local-suffix, value tel-local-suffix, value tel-national, value tel-national, value tel-national, value tel-national, value tel-national, value tel-national, value tel-national, value transaction-amount, value transaction-amount, value transaction-amount, value transaction-amount, value transaction-amount, value transaction-amount, value transaction-amount, value transaction-currency, value transaction-currency, value transaction-currency, value transaction-currency, value transaction-currency, value transaction-currency, value transaction-currency, value url, value url, value url, value url, value url, value url, value url, value username, value username, value username, value username, value username, value username, value username, value work, value work, value work, value work, value work, value work, value work
HTMLFormElement.autocomplete (WebIDL attribute) §: Defined in HTML
HTMLInputElement.autocomplete (WebIDL attribute) §
HTMLSelectElement.autocomplete (WebIDL attribute) §
HTMLTextAreaElement.autocomplete (WebIDL attribute) §: Defined in HTML
autocorrect (markup attribute for html-global ) §: Defined in HTML; Related terms: value off, value on
HTMLElement.autocorrect (WebIDL attribute) §: Defined in HTML
:autofill (CSS selector) §: Defined in Selectors 4
Autofill and credentialless iframe (concept) §: Defined in Iframe credentialless
autofocus (markup attribute for html-global ) §: Defined in HTML; Referenced in HTML Accessibility API Mappings 1.0
autofocus (markup attribute for core-attributes ) §: Defined in SVG 2; Referenced in SVG Animations 2, SVG Paths
HTMLOrSVGElement.autofocus (WebIDL attribute) §: Defined in HTML
MediaTrackCapabilities.autoGainControl (WebIDL dictionary member) §: Defined in Media Capture and Streams
MediaTrackConstraintSet.autoGainControl (WebIDL dictionary member) §: Defined in Media Capture and Streams
MediaTrackSettings.autoGainControl (WebIDL dictionary member) §: Defined in Media Capture and Streams
MediaTrackSupportedConstraints.autoGainControl (WebIDL dictionary member) §: Defined in Media Capture and Streams
IDBObjectStore.autoIncrement (WebIDL attribute) §: Defined in Indexed DB 3.0
IDBObjectStoreParameters.autoIncrement (WebIDL dictionary member) §: Defined in Indexed DB 3.0
AutoKeyword (WebIDL enumeration) §: Defined in WebVTT: The Web Video Text Tracks Format; Related terms: value auto; see also WebIDLPedia
BluetoothRemoteGATTCharacteristic.[[automatedCharacteristicReadResponse]] (internal slot) §: Defined in Web Bluetooth
BluetoothRemoteGATTCharacteristic.[[automatedCharacteristicReadResponseData]] (internal slot) §: Defined in Web Bluetooth
BluetoothRemoteGATTCharacteristic.[[automatedCharacteristicSubscribeToNotificationsResponse]] (internal slot) §: Defined in Web Bluetooth
BluetoothRemoteGATTCharacteristic.[[automatedCharacteristicUnsubscribeFromNotificationsResponse]] (internal slot) §: Defined in Web Bluetooth
BluetoothRemoteGATTCharacteristic.[[automatedCharacteristicWriteResponse]] (internal slot) §: Defined in Web Bluetooth
BluetoothRemoteGATTDescriptor.[[automatedDescriptorReadResponse]] (internal slot) §: Defined in Web Bluetooth
BluetoothRemoteGATTDescriptor.[[automatedDescriptorReadResponseData]] (internal slot) §: Defined in Web Bluetooth
BluetoothRemoteGATTDescriptor.[[automatedDescriptorWriteResponse]] (internal slot) §: Defined in Web Bluetooth
BluetoothRemoteGATTServer.[[automatedGATTConnectionResponse]] (internal slot) §: Defined in Web Bluetooth
automatic beacon event type (concept for fencedframetype ) §: Defined in Fenced Frame; Referenced in Protected Audience
automatic block size (concept) §: Defined in CSS Sizing 3; Referenced in CSS Flexbox 1, CSS Overflow 4
automatic grid position (concept) §: Defined in CSS Grid Layout 1 , CSS Grid Layout 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Grid Layout 3
automatic grid span (concept) §: Defined in CSS Grid Layout 2
automatic inline size (concept) §: Defined in CSS Sizing 3; Referenced in CSS Writing Modes 4
automatic minimum size (concept) §: Defined in CSS Sizing 3; Referenced in CSS Flexbox 1, CSS Positioned Layout 3, CSS Sizing 4
automatic size (concept) §: Defined in CSS Sizing 3; Referenced in CSS Flexbox 1, CSS Inline Layout 3, CSS Positioned Layout 3, CSS Ruby Annotation Layout 1, CSS Sizing 4, CSS Writing Modes 3
AutomationRate (WebIDL enumeration) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: value a-rate, value k-rate; see also WebIDLPedia
AudioParam.automationRate (WebIDL attribute) §
AudioParam.automationRate (WebIDL attribute) §: Defined in Web Audio API , Web Audio API 1.1
AudioParamDescriptor.automationRate (WebIDL dictionary member) §
AudioParamDescriptor.automationRate (WebIDL dictionary member) §: Defined in Web Audio API , Web Audio API 1.1
autonomous custom element (concept) §: Defined in HTML; Referenced in HTML Accessibility API Mappings 1.0, ARIA in HTML
autoplay (markup attribute for audio, video element ) §: Defined in HTML; Referenced in HTML Accessibility API Mappings 1.0
autoplay (markup attribute for model ) §: Defined in The <model> element
HTMLMediaElement.autoplay (WebIDL attribute) §: Defined in HTML; Referenced in Media Capture and Streams
AutoplayPolicy (WebIDL enumeration) §: Defined in Autoplay Policy Detection; Related terms: value allowed, value allowed-muted, value disallowed, value Inaudible media, value inaudible media element; see also WebIDLPedia
AutoplayPolicyMediaType (WebIDL enumeration) §: Defined in Autoplay Policy Detection; Related terms: value audiocontext, value mediaelement; see also WebIDLPedia
<autospace> (CSS type) §: Defined in CSS Text 4
<autospace> (CSS value for text-spacing ) §: Defined in CSS Text 4
"auxiliary" (value for FrameType WebIDL enumeration) §: Defined in Service Workers
auxiliary browsing context (concept) §: Defined in HTML; Referenced in Document Picture-in-Picture, Prerendering Revamped, CSSOM View, Service Workers
av01 (concept for AV1 Image Item Type ) §: Defined in AVIF
av01 (CSS value for ISOBMFF Brand ) §: Defined in AV1 Codec ISO Media File Format Binding
av01 (CSS value for AV1SampleEntry ) §: Defined in AV1 Codec ISO Media File Format Binding
VideoEncoderEncodeOptions.av1 (WebIDL dictionary member) §: Defined in AV1 WebCodecs Registration
AV1 Alpha Image Item (concept) §: Defined in AVIF
AV1 Alpha Image Sequence (concept) §: Defined in AVIF
AV1 Auxiliary Image Item (concept) §: Defined in AVIF
AV1 Auxiliary Image Sequence (concept) §: Defined in AVIF
AV1 Depth Image Item (concept) §: Defined in AVIF
AV1 Depth Image Sequence (concept) §: Defined in AVIF
AV1 Image File Format (concept) §: Defined in AVIF
AV1 Image Item (concept) §: Defined in AVIF
AV1 Image Item Data (concept) §: Defined in AVIF
AV1 Image Sequence (concept) §: Defined in AVIF
av1C (concept for AV1ItemConfigurationProperty ) §: Defined in AVIF
av1C (concept) §: Defined in AV1 Codec ISO Media File Format Binding
av1f (concept) §: Defined in AV1 Codec ISO Media File Format Binding
AV1ItemConfigurationProperty (concept) §: Defined in AVIF; Related terms: concept av1C
AV1LayeredImageIndexingProperty (concept) §: Defined in AVIF; Related terms: concept a1lx
av1m (CSS value for AV1MultiFrameSampleGroupEntry ) §: Defined in AV1 Codec ISO Media File Format Binding
av1s (concept) §: Defined in AV1 Codec ISO Media File Format Binding
Availability (WebIDL enumeration) §: Defined in Writing Assistance APIs; Referenced in Translator and Language Detector APIs; Related terms: concept minimum availability, value available, value downloadable, value downloading, value unavailable; see also WebIDLPedia
LanguageDetector.availability(options) (WebIDL operation) §: Defined in Translator and Language Detector APIs
Rewriter.availability(options) (WebIDL operation) §: Defined in Writing Assistance APIs
Summarizer.availability(options) (WebIDL operation) §: Defined in Writing Assistance APIs
Translator.availability(options) (WebIDL operation) §: Defined in Translator and Language Detector APIs
Writer.availability(options) (WebIDL operation) §: Defined in Writing Assistance APIs
availabilitychanged (event for Bluetooth ) §: Defined in Web Bluetooth
AvailabilityStatus (WebIDL enumeration) §: Defined in Web Speech API; Related terms: value available, value downloadable, value downloading, value unavailable; see also WebIDLPedia
"available" (value for AvailabilityStatus WebIDL enumeration) §: Defined in Web Speech API
"available" (value for Availability WebIDL enumeration) §: Defined in Writing Assistance APIs; Referenced in Translator and Language Detector APIs
"available" (value for SecurePaymentConfirmationAvailability WebIDL enumeration) §: Defined in Secure Payment Confirmation
available font faces (concept) §: Defined in CSS Font Loading 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
Available Locales List (concept) §: Defined in ECMAScript® 2026 Internationalization API
available named time zone identifier (concept for ECMAScript ) §: Defined in ECMAScript
available named time zones (concept for ECMAScript ) §: Defined in ECMAScript
available space (concept) §: Defined in CSS Sizing 3; Referenced in CSS Box Alignment 3, CSS Flexbox 1, CSS Grid Layout 3, CSS Layout API 1, CSS Multicol 2, CSS Positioned Layout 3, CSS Writing Modes 3, CSS Writing Modes 4
available to element internals (concept for ShadowRoot ) §: Defined in DOM; Referenced in HTML
SpeechRecognition.available(options) (WebIDL operation) §: Defined in Web Speech API
LayoutConstraints.availableBlockSize (WebIDL attribute) §: Defined in CSS Layout API 1
LayoutConstraintsOptions.availableBlockSize (WebIDL dictionary member) §: Defined in CSS Layout API 1
RTCIceCandidatePairStats.availableIncomingBitrate (WebIDL dictionary member) §: Defined in WebRTC Statistics
LayoutConstraints.availableInlineSize (WebIDL attribute) §: Defined in CSS Layout API 1
LayoutConstraintsOptions.availableInlineSize (WebIDL dictionary member) §: Defined in CSS Layout API 1
AvailableNamedTimeZoneIdentifiers (algorithm) §: Defined in ECMAScript; Referenced in ECMAScript® 2026 Internationalization API, WebDriver BiDi
RTCIceCandidatePairStats.availableOutgoingBitrate (WebIDL dictionary member) §: Defined in WebRTC Statistics
Screen.availHeight (WebIDL attribute) §: Defined in CSSOM View
ScreenDetailed.availLeft (WebIDL attribute) §: Defined in Window Management
ScreenDetailed.availTop (WebIDL attribute) §: Defined in Window Management
Screen.availWidth (WebIDL attribute) §: Defined in CSSOM View
"avc" (value for AvcBitstreamFormat WebIDL enumeration) §: Defined in H.264
VideoEncoderConfig.avc (WebIDL dictionary member) §: Defined in H.264
VideoEncoderEncodeOptions.avc (WebIDL dictionary member) §: Defined in H.264
AvcBitstreamFormat (WebIDL enumeration) §: Defined in H.264; Related terms: value annexb, value avc; see also WebIDLPedia
AvcEncoderConfig (WebIDL dictionary) §: Defined in H.264; Related terms: AvcEncoderConfig.format; see also WebIDLPedia
AudioPlayoutStats.[[average latency]] (internal slot) §: Defined in Playout Statistics API for WebAudio
AudioPlayoutStats.averageLatency (WebIDL attribute) §: Defined in Playout Statistics API for WebAudio
MLOpSupportLimits.averagePool2d (WebIDL dictionary member) §: Defined in Web Neural Network API
MLGraphBuilder.averagePool2d(input, options) (WebIDL operation) §: Defined in Web Neural Network API
AVIF (concept) §: Defined in AVIF
avif (concept for AVIF Image brand ) §: Defined in AVIF
AVIF Advanced Profile (concept) §: Defined in AVIF; Related terms: concept MA1A
AVIF Baseline Profile (concept) §: Defined in AVIF; Related terms: concept MA1B
AVIF file (concept) §: Defined in AVIF
avio (concept for AVIF Intra-only brand ) §: Defined in AVIF
avis (concept for AVIF Image Sequence brand ) §: Defined in AVIF
avoid (CSS value for break-after, break-before property ) §: Defined in CSS Fragmentation 3 , CSS Fragmentation 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Regions 1
avoid (CSS value for break-inside, page-break-inside property ) §: Defined in CSS Fragmentation 3 , CSS Fragmentation 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
avoid (CSS value for wrap-inside ) §: Defined in CSS Text 4
avoid (CSS value for wrap-after, wrap-before property ) §: Defined in CSS Text 4
avoid (CSS value for page-break-after, page-break-before property, page-break-inside property ) §: Defined in CSS 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2025
avoid-column (CSS value for break-after, break-before property ) §: Defined in CSS Fragmentation 3 , CSS Fragmentation 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
avoid-column (CSS value for break-inside, page-break-inside property ) §: Defined in CSS Fragmentation 3 , CSS Fragmentation 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
avoid-flex (CSS value for wrap-after, wrap-before property ) §: Defined in CSS Text 4
avoid-line (CSS value for wrap-after, wrap-before property ) §: Defined in CSS Text 4
avoid-orphans (CSS value for text-wrap-style ) §: Defined in CSS Text 4
avoid-page (CSS value for break-after, break-before property ) §: Defined in CSS Fragmentation 3 , CSS Fragmentation 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
avoid-page (CSS value for break-inside, page-break-inside property ) §: Defined in CSS Fragmentation 3 , CSS Fragmentation 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
avoid-region (CSS value for break-after, break-before property ) §: Defined in CSS Fragmentation 3 , CSS Fragmentation 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Regions 1
avoid-region (CSS value for break-inside, page-break-inside property ) §: Defined in CSS Fragmentation 3 , CSS Fragmentation 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
Await (algorithm) §: Defined in ECMAScript; Referenced in ES Array.fromAsync, ECMAScript Async Explicit Resource Management, ECMAScript Explicit Resource Management, WebAssembly JavaScript Interface: Promise Integration, Observable, WebDriver BiDi
awaits (concept) §: Defined in WebDriver BiDi
CSSSkew.ax (WebIDL attribute) §: Defined in CSS Typed OM 1
CSSSkewX.ax (WebIDL attribute) §: Defined in CSS Typed OM 1
Gamepad.axes (WebIDL attribute) §: Defined in Gamepad
MLLayerNormalizationOptions.axes (WebIDL dictionary member) §: Defined in Web Neural Network API
MLReduceOptions.axes (WebIDL dictionary member) §: Defined in Web Neural Network API
MLResample2dOptions.axes (WebIDL dictionary member) §: Defined in Web Neural Network API
MLReverseOptions.axes (WebIDL dictionary member) §: Defined in Web Neural Network API
axis (markup attribute for td, th element ) §: Defined in HTML
HTMLTableCellElement.axis (WebIDL attribute) §: Defined in HTML
MLBatchNormalizationOptions.axis (WebIDL dictionary member) §: Defined in Web Neural Network API
MLGatherOptions.axis (WebIDL dictionary member) §: Defined in Web Neural Network API
MLScatterOptions.axis (WebIDL dictionary member) §: Defined in Web Neural Network API
MLSplitOptions.axis (WebIDL dictionary member) §: Defined in Web Neural Network API
PointerTimeline.axis (WebIDL attribute) §: Defined in Pointer-driven Animations
PointerTimelineOptions.axis (WebIDL dictionary member) §: Defined in Pointer-driven Animations
ScrollTimeline.axis (WebIDL attribute) §: Defined in Scroll-driven Animations
ScrollTimelineOptions.axis (WebIDL dictionary member) §: Defined in Scroll-driven Animations
ViewTimelineOptions.axis (WebIDL dictionary member) §: Defined in Scroll-driven Animations
axis-lock (concept) §: Defined in CSS Scroll Snap 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
FontFaceVariationAxis.axisTag (WebIDL attribute) §: Defined in CSS Font Loading 3
CSSSkew.ay (WebIDL attribute) §: Defined in CSS Typed OM 1
CSSSkewY.ay (WebIDL attribute) §: Defined in CSS Typed OM 1
azimuth (markup attribute for feDistantLight ) §: Defined in Filter Effects 1
SVGFEDistantLightElement.azimuth (WebIDL attribute) §: Defined in Filter Effects 1
PointerEvent.azimuthAngle (WebIDL attribute) §
PointerEvent.azimuthAngle (WebIDL attribute) §: Defined in Pointer Events , Pointer Events
PointerEventInit.azimuthAngle (WebIDL dictionary member) §
PointerEventInit.azimuthAngle (WebIDL dictionary member) §: Defined in Pointer Events , Pointer Events
Touch.azimuthAngle (WebIDL attribute) §: Defined in Touch Events
TouchInit.azimuthAngle (WebIDL dictionary member) §: Defined in Touch Events
"aztec" (value for BarcodeFormat WebIDL enumeration) §: Defined in Accelerated Shape Detection in Images
azure (concept) §: Defined in CSS Color 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
azure (CSS value for <color>, <named-color> type ) §: Defined in CSS Color 4