Terms starting with letter o

Color key: WebIDL CSS Markup HTTP

"object" (value for RequestDestination WebIDL enumeration) §: Defined in Fetch
object (markup element) §: Defined in HTML; Referenced in Scripting Policy, Manifest Incubations, Measure Memory API, Content Security Policy 3, CSS Display 3, CSS Display 4, CSS User Interface 3, CSS User Interface 4, EPUB 3.3, EPUB 3.4, EPUB Reading Systems 3.3, EPUB Reading Systems 3.4, GPC, HTML Accessibility API Mappings 1.0, ARIA in HTML, Image Resource, Long Tasks API, Resource Timing, Selectors 4; Related terms: concept form owner, markup attribute align, markup attribute archive, markup attribute autocomplete, markup attribute border, markup attribute classid, markup attribute code, markup attribute codebase, markup attribute codetype, markup attribute data, markup attribute declare, markup attribute disabled, markup attribute form, markup attribute height, markup attribute hspace, markup attribute name, markup attribute standby, markup attribute type, markup attribute typemustmatch, markup attribute usemap, markup attribute vspace, markup attribute width
object (WebIDL interface) §: Defined in Web IDL; Referenced in Console, HTML, Streams, Element Timing API, 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 Bluetooth Scanning, Playout Statistics API for WebAudio, Handwriting Recognition API, Layout Instability API, Requesting Permissions, Relinquishing Permissions, Shared Storage API, Protected Audience, Managed Configuration API, Compute Pressure 1, Contact Picker API, Digital Credentials, Event Timing API, Geolocation, Geometry Interfaces 1, High Resolution Time, Largest Contentful Paint, Long Tasks API, Media Capture and Streams, Media Session, Navigation Timing 2, Paint Timing, Payment Handler API, Payment Request API, Performance Timeline, Permissions Policy, Permissions, Resource Timing, Server Timing, Service Workers, WebAssembly JavaScript Interface, WebAssembly Web API, Web Animations, Web Audio API, Web Audio API 1.1, Web Authentication, Web Cryptography 2, WebRTC Encoded Transform, WebRTC 1.0; see also WebIDLPedia
object (concept) §: Defined in RDF 1.2 Concepts and Abstract Data Model; Referenced in Reporting API
RdfTriple.object (WebIDL attribute) §: Defined in JSON-LD 1.1 Processing Algorithms and API
Object (WebIDL interface) §: Defined in ECMAScript; Referenced in Ambient Light Sensor, CSS Viewport 1, Generic Sensor API, Geolocation Sensor, Indexed DB 3.0, Magnetometer, Device Orientation and Motion, Proximity Sensor; Related terms: new Object(value), Object.assign(target, ...sources), Object.create(O, Properties), Object.defineProperties(O, Properties), Object.defineProperty(O, P, Attributes), Object.entries(O), Object.freeze(O), Object.fromEntries(iterable), Object.getOwnPropertyDescriptor(O, P), Object.getOwnPropertyDescriptors(O), Object.getOwnPropertyNames(O), Object.getOwnPropertySymbols(O), Object.getPrototypeOf(O), Object.groupBy(items, callback), Object.hasOwn(O, P), Object.hasOwnProperty(V), Object.is(value1, value2), Object.isExtensible(O), Object.isFrozen(O), Object.isPrototypeOf(V), Object.isSealed(O), Object.keys(O), Object.preventExtensions(O), Object.propertyIsEnumerable(V), Object.seal(O), Object.setPrototypeOf(O, proto), Object.toLocaleString(reserved1, reserved2), Object.toString(), Object.valueOf(), Object.values(O); see also WebIDLPedia
object bounding box (concept) §: Defined in SVG 2; Referenced in CSS Box Model 3, CSS Box Model 4, CSS Masking 1, CSS Transforms 1
Object Environment Record (concept for ECMAScript ) §: Defined in ECMAScript; Related terms: algorithm CreateImmutableBinding(N, S), algorithm CreateMutableBinding(N, D), algorithm DeleteBinding(N), algorithm GetBindingValue(N, S), algorithm HasBinding(N), algorithm HasSuperBinding(), algorithm HasThisBinding(), algorithm InitializeBinding(N, V), algorithm SetMutableBinding(N, V, S), algorithm WithBaseObject()
object size negotiation (concept) §: Defined in CSS Images 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Images 4, CSS Painting API 1
Object type (concept for ECMAScript ) §: Defined in ECMAScript
object types (concept) §: Defined in Web IDL
object-fit (CSS property) §: Defined in CSS Images 3 , CSS Images 4; Referenced in CSS Images 5, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Sizing 4, CSS Typed OM 1, CSS User Interface 4; Related terms: CSS value contain, CSS value cover, CSS value fill, CSS value none, CSS value scale-down
object-position (CSS property) §: Defined in CSS Images 3; Referenced in CSS Images 5, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Images 4, CSS Values 3, Largest Contentful Paint
object-src (concept) §: Defined in Content Security Policy 3; Referenced in Credential Management 1
object-view-box (CSS property) §: Defined in CSS Images 5; Referenced in CSS Images 4; Related terms: CSS value none
%Object.prototype% (WebIDL interface) §: Defined in ECMAScript; Referenced in HTML, Streams, ECMAScript® 2026 Internationalization API, Uint8Array to/from base64, ECMAScript Async Explicit Resource Management, ECMAScript Explicit Resource Management, Intl.DurationFormat, Intl Locale Info, JSON.parse source text access, ShadowRealm API, Source Phase Imports, Temporal, Web IDL; see also WebIDLPedia
new Object(value) (WebIDL constructor) §: Defined in ECMAScript
%Object% (WebIDL interface) §: Defined in ECMAScript; Referenced in ECMAScript Async Explicit Resource Management, ECMAScript Explicit Resource Management, Source Phase Imports; see also WebIDLPedia
objectBoundingBox (CSS value for clipPathUnits ) §: Defined in CSS Masking 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
objectBoundingBox (CSS value for maskUnits ) §: Defined in CSS Masking 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
objectBoundingBox (CSS value for maskContentUnits ) §: Defined in CSS Masking 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
objectBoundingBox (value for filterUnits ) §: Defined in Filter Effects 1
objectBoundingBox (value for primitiveUnits ) §: Defined in Filter Effects 1
ObjectDefineProperties (algorithm) §: Defined in ECMAScript
IDBIndex.objectStore (WebIDL attribute) §: Defined in Indexed DB 3.0
IDBTransaction.objectStore(name) (WebIDL operation) §: Defined in Indexed DB 3.0
IDBDatabase.objectStoreNames (WebIDL attribute) §: Defined in Indexed DB 3.0
IDBTransaction.objectStoreNames (WebIDL attribute) §: Defined in Indexed DB 3.0
oblique (CSS value for font-style ) §: Defined in CSS 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2025, CSS Fonts 4
oblique <angle [-90deg,90deg]>? (CSS value for font-style ) §: Defined in CSS Fonts 4; Referenced in CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
oblique-only (CSS value for font-synthesis-style ) §: Defined in CSS Fonts 4; Referenced in CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
Observable (WebIDL interface) §: Defined in Observable; Related terms: new Observable(callback), Observable.catch(callback), Observable.drop(amount), Observable.every(predicate, options), Observable.filter(predicate), Observable.finally(callback), Observable.find(predicate, options), Observable.first(options), Observable.flatMap(mapper), Observable.forEach(callback, options), Observable.from(value), Observable.inspect(inspectorUnion), Observable.last(options), Observable.map(mapper), Observable.reduce(reducer, initialValue, options), Observable.some(predicate, options), Observable.subscribe(observer, options), Observable.switchMap(mapper), Observable.take(amount), Observable.takeUntil(value), Observable.toArray(options); see also WebIDLPedia
observable array type (concept) §: Defined in Web IDL; Referenced in Web Platform Design Principles
new Observable(callback) (WebIDL constructor) §: Defined in Observable
ObservableArray (WebIDL interface) §: Defined in Web IDL; Referenced in Web Speech API, CSS Typed OM 1, CSSOM; see also WebIDLPedia
ObservableEventListenerOptions (WebIDL dictionary) §: Defined in Observable; Related terms: ObservableEventListenerOptions.capture, ObservableEventListenerOptions.passive; see also WebIDLPedia
ObservableInspector (WebIDL dictionary) §: Defined in Observable; Related terms: ObservableInspector.abort, ObservableInspector.complete, ObservableInspector.error, ObservableInspector.next, ObservableInspector.subscribe; see also WebIDLPedia
ObservableInspectorAbortHandler (WebIDL callback) §: Defined in Observable
ObservableInspectorUnion (WebIDL type alias) §: Defined in Observable; see also WebIDLPedia
ObservableSubscriptionCallback (WebIDL callback) §: Defined in Observable
IntersectionObserver.[[ObservationTargets]] (internal slot) §: Defined in Intersection Observer
ResizeObserver.[[observationTargets]] (internal slot) §: Defined in Resize Observer
Observe-Browsing-Topics: (HTTP header) §: Defined in Topics API
PerformanceObserver.observe() (WebIDL operation) §: Defined in Performance Timeline
PressureObserver.observe() (WebIDL operation) §: Defined in Compute Pressure 1
ReportingObserver.observe() (WebIDL operation) §: Defined in Reporting API
MutationObserver.observe(target, options) (WebIDL operation) §: Defined in DOM; Referenced in Intersection Observer
ResizeObserver.observe(target, options) (WebIDL operation) §: Defined in Resize Observer
IntersectionObserver.observe(target) (WebIDL operation) §: Defined in Intersection Observer; Referenced in HTML
ResizeObservation.observedBox (WebIDL attribute) §: Defined in Resize Observer
IntersectionObserverRegistration.observer (WebIDL attribute) §: Defined in Intersection Observer
ObserverUnion (WebIDL type alias) §: Defined in Observable; see also WebIDLPedia
Obsolete Recommendation (concept) §: Defined in W3C Process Document; Referenced in WoT Bindings Registry
Obsolete Registry (concept) §: Defined in W3C Process Document
obtain a blob object (concept) §: Defined in File API; Referenced in Fetch, HTML
obtain a connection (concept) §: Defined in Fetch; Referenced in HTML, Fenced Frame, Local Network Access, Prefetch, WebTransport; Related terms: concept requireUnreliable
obtain a local storage bottle map (concept) §: Defined in Storage; Referenced in File System, HTML, Storage Buckets API, Service Workers, Web Locks API
obtain a Scripting Policy from a Structured Header (algorithm) §: Defined in Scripting Policy
obtain a Scripting Policy pair from a response (algorithm) §: Defined in Scripting Policy
obtain a service worker agent (concept) §: Defined in HTML; Referenced in Service Workers
obtain a session storage bottle map (concept) §: Defined in Storage; Referenced in HTML
obtain a site (concept) §: Defined in HTML; Referenced in Fetch, Navigational-Tracking Mitigations, requestStorageAccessFor API, The Storage Access API, Iframe credentialless, Attribution Reporting, User Agent Interaction with Related Website Sets, Prefetch, Shared Storage API, Privacy-Preserving Attribution 1
obtain a storage key (concept) §: Defined in Storage; Referenced in Indexed DB 3.0, Service Workers
obtain a storage key for non-storage purposes (concept) §: Defined in Storage; Referenced in HTML, Extending Storage Access API to non-cookie storage, Iframe credentialless, Isolated Contexts, File API
obtain a WebSocket connection (concept) §: Defined in WebSockets; Referenced in Fetch
obtain an embedder policy (concept) §: Defined in HTML
obtain the Private Aggregation coordinator (concept) §: Defined in Private Aggregation API; Referenced in Shared Storage API, Protected Audience
obtain-directive (algorithm) §: Defined in Isolated Contexts
"occlusion" (value for GPUQueryType WebIDL enumeration) §: Defined in WebGPU
GPURenderPassEncoder.[[occlusion_query_active]] (internal slot) §: Defined in WebGPU
GPURenderPassEncoder.[[occlusion_query_set]] (internal slot) §: Defined in WebGPU
[[occlusionQueryIndex]] (internal slot for RenderState ) §: Defined in WebGPU
GPURenderPassDescriptor.occlusionQuerySet (WebIDL dictionary member) §: Defined in WebGPU
OCF abstract container (concept) §: Defined in EPUB 3.3 , EPUB 3.4
OCF ZIP container (concept) §: Defined in EPUB 3.3 , EPUB 3.4
octet (WebIDL interface) §: Defined in Web IDL; Referenced in Direct Sockets API, Web Serial API, Modern Algorithms in the Web Cryptography API, WebHID API, WebUSB API, Web Platform Design Principles, Gamepad, Linear PCM WebCodecs Registration, WebCodecs, Web Cryptography 2, Web MIDI API, WebRTC Encoded Transform, WebRTC 1.0; see also WebIDLPedia
"odd" (value for ParityType WebIDL enumeration) §: Defined in Web Serial API
Array.of(...items) (WebIDL operation) §: Defined in ECMAScript
off (value for autocomplete attribute of form element ) §: Defined in HTML
off (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
off (value for autocapitalize attribute of html-global ) §: Defined in HTML
off (value for autocorrect attribute of html-global ) §: Defined in HTML
"off" (value for FillLightMode WebIDL enumeration) §: Defined in MediaStream Image Capture
"offer" (value for RTCSdpType WebIDL enumeration) §: Defined in WebRTC 1.0
RTCOfferOptions.offerToReceiveAudio (WebIDL dictionary member) §: Defined in WebRTC 1.0
RTCOfferOptions.offerToReceiveVideo (WebIDL dictionary member) §: Defined in WebRTC 1.0
offline (event for Window, WorkerGlobalScope interface ) §: Defined in HTML
OfflineAudioCompletionEvent (WebIDL interface) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefinedrenderedBuffer, undefinedOfflineAudioCompletionEvent(type, eventInitDict); see also WebIDLPedia
new OfflineAudioCompletionEvent(type, eventInitDict) (WebIDL constructor) §
new OfflineAudioCompletionEvent(type, eventInitDict) (WebIDL constructor) §: Defined in Web Audio API , Web Audio API 1.1
OfflineAudioCompletionEventInit (WebIDL dictionary) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefinedrenderedBuffer; see also WebIDLPedia
OfflineAudioContext (WebIDL interface) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefinedlength, undefinedoncomplete, undefined[[rendered buffer]], undefined[[rendering started]], undefinedOfflineAudioContext(contextOptions), undefinedOfflineAudioContext(numberOfChannels, length, sampleRate), event complete, undefinedresume(), undefinedstartRendering(), undefinedsuspend(suspendTime); see also WebIDLPedia
new OfflineAudioContext(contextOptions) (WebIDL constructor) §
new OfflineAudioContext(contextOptions) (WebIDL constructor) §: Defined in Web Audio API , Web Audio API 1.1
new OfflineAudioContext(numberOfChannels, length, sampleRate) (WebIDL constructor) §
new OfflineAudioContext(numberOfChannels, length, sampleRate) (WebIDL constructor) §: Defined in Web Audio API , Web Audio API 1.1
OfflineAudioContextOptions (WebIDL dictionary) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefinedlength, undefinednumberOfChannels, undefinedrenderSizeHint, undefinedsampleRate; see also WebIDLPedia
OffscreenCanvas (WebIDL interface) §: Defined in HTML; Referenced in CSS Font Loading 3, WebCodecs, WebGPU; Related terms: OffscreenCanvas.canvas, OffscreenCanvas.height, OffscreenCanvas.oncontextlost, OffscreenCanvas.oncontextrestored, OffscreenCanvas.width, new new OffscreenCanvas(width, height), event contextlost, event contextrestored, OffscreenCanvas.convertToBlob(options), OffscreenCanvas.getContext(contextId, options), OffscreenCanvas.transferToImageBitmap(); see also WebIDLPedia
OffscreenCanvasRenderingContext2D (WebIDL interface) §: Defined in HTML; see also WebIDLPedia
OffscreenRenderingContext (WebIDL type alias) §: Defined in HTML; see also WebIDLPedia
OffscreenRenderingContextId (WebIDL enumeration) §: Defined in HTML; see also WebIDLPedia
offset (concept for boundary point ) §: Defined in DOM; Referenced in execCommand, Selection API
offset (markup attribute for feComponentTransfer ) §: Defined in Filter Effects 1
offset (CSS property) §: Defined in Motion Path 1; Referenced in CSS Transforms 2, CSS Typed OM 1, Web Animations
offset (markup attribute for stop ) §: Defined in SVG 2
BaseComputedKeyframe.offset (WebIDL dictionary member) §: Defined in Web Animations
BaseKeyframe.offset (WebIDL dictionary member) §: Defined in Web Animations
BasePropertyIndexedKeyframe.offset (WebIDL dictionary member) §: Defined in Web Animations
CaretPosition.offset (WebIDL attribute) §: Defined in CSSOM View
ConstantSourceNode.offset (WebIDL attribute) §
ConstantSourceNode.offset (WebIDL attribute) §: Defined in Web Audio API , Web Audio API 1.1
ConstantSourceOptions.offset (WebIDL dictionary member) §
ConstantSourceOptions.offset (WebIDL dictionary member) §: Defined in Web Audio API , Web Audio API 1.1
GPUBufferBinding.offset (WebIDL dictionary member) §: Defined in WebGPU
GPUCompilationMessage.offset (WebIDL attribute) §: Defined in WebGPU
GPUTexelCopyBufferLayout.offset (WebIDL dictionary member) §: Defined in WebGPU
GPUVertexAttribute.offset (WebIDL dictionary member) §: Defined in WebGPU
PASignalValue.offset (WebIDL dictionary member) §: Defined in Protected Audience
PlaneLayout.offset (WebIDL dictionary member) §: Defined in WebCodecs
SVGComponentTransferFunctionElement.offset (WebIDL attribute) §: Defined in Filter Effects 1
SVGStopElement.offset (WebIDL attribute) §: Defined in SVG 2
TimelineRangeOffset.offset (WebIDL dictionary member) §: Defined in Web Animations 2
offset anchor point (concept) §: Defined in Motion Path 1
offset field (concept) §: Defined in Source map format
offset path (concept) §: Defined in Motion Path 1
offset position (concept) §: Defined in Motion Path 1
offset starting position (concept) §: Defined in Motion Path 1
offset time zones (concept for ECMAScript ) §: Defined in ECMAScript
offset transform (concept) §: Defined in Motion Path 1
offset-anchor (CSS property) §: Defined in Motion Path 1; Referenced in CSS Typed OM 1; Related terms: CSS value auto
offset-distance (CSS property) §: Defined in Motion Path 1; Referenced in CSS Round Display 1, CSS Typed OM 1
<offset-path> (CSS type) §: Defined in Motion Path 1
offset-path (CSS property) §: Defined in Motion Path 1; Referenced in CSS Anchor Positioning, CSS Round Display 1, CSS Typed OM 1; Related terms: CSS value <offset-path> || <coord-box>, CSS value none, CSS value <ray()>
offset-position (CSS property) §: Defined in Motion Path 1; Referenced in CSS Round Display 1, CSS Typed OM 1; Related terms: CSS value auto, CSS value normal
offset-rotate (CSS property) §: Defined in Motion Path 1; Referenced in CSS Typed OM 1; Related terms: CSS value auto, CSS value reverse
HTMLElement.offsetHeight (WebIDL attribute) §: Defined in CSSOM View
HTMLElement.offsetLeft (WebIDL attribute) §: Defined in CSSOM View
VisualViewport.offsetLeft (WebIDL attribute) §: Defined in CSSOM View
CaretPosition.offsetNode (WebIDL attribute) §: Defined in CSSOM View
HTMLElement.offsetParent (WebIDL attribute) §: Defined in CSSOM View
XRHitTestOptionsInit.offsetRay (WebIDL dictionary member) §: Defined in WebXR Hit Test
XRTransientInputHitTestOptionsInit.offsetRay (WebIDL dictionary member) §: Defined in WebXR Hit Test
HTMLElement.offsetTop (WebIDL attribute) §: Defined in CSSOM View; Referenced in Web Platform Design Principles
VisualViewport.offsetTop (WebIDL attribute) §: Defined in CSSOM View
HTMLElement.offsetWidth (WebIDL attribute) §: Defined in CSSOM View
MouseEvent.offsetX (WebIDL attribute) §: Defined in CSSOM View; Referenced in Pointer-driven Animations
MouseEvent.offsetY (WebIDL attribute) §: Defined in CSSOM View; Referenced in Pointer-driven Animations
"ogg" (value for OpusBitstreamFormat WebIDL enumeration) §: Defined in Opus WebCodecs Registration
"ohwi" (value for MLConv2dFilterOperandLayout WebIDL enumeration) §: Defined in Web Neural Network API
"ohwi" (value for MLConvTranspose2dFilterOperandLayout WebIDL enumeration) §: Defined in Web Neural Network API
"oihw" (value for MLConv2dFilterOperandLayout WebIDL enumeration) §: Defined in Web Neural Network API
"ok" (value for USBTransferStatus WebIDL enumeration) §: Defined in WebUSB API
Response.ok (WebIDL attribute) §: Defined in Fetch
ok status (concept) §: Defined in Fetch; Referenced in HTML, Background Fetch, Prefetch, Shared Storage API, Protected Audience, A Well-Known URL for Changing Passwords, Federated Credential Management API, Payment Method Manifest, Reporting API, Service Workers, WebAssembly Web API
Oklab (CSS value for oklab() ) §: Defined in CSS Color 4; Referenced in CSS Color 5
oklab() (CSS function) §: Defined in CSS Color 4 , CSS Color 5; Referenced in CSS Color HDR 1, CSS Typed OM 1; Related terms: CSS value a, CSS value alpha, CSS value b, CSS value l, CSS value Oklab
OkLCh (CSS value for oklch() ) §: Defined in CSS Color 4; Referenced in CSS Color 5
oklch() (CSS function) §: Defined in CSS Color 4 , CSS Color 5; Referenced in CSS Color HDR 1, CSS Typed OM 1; Related terms: CSS value alpha, CSS value c, CSS value h, CSS value l, CSS value OkLCh
ol (markup element) §: Defined in HTML; Referenced in execCommand, CSS Lists 3, EPUB 3.3, EPUB 3.4, HTML Accessibility API Mappings 1.0, ARIA in HTML, Publication Manifest, Selectors 4, WAI-ARIA, WAI-ARIA; Related terms: markup attribute compact, markup attribute reversed, markup attribute start, markup attribute type
old (CSS value for voice-family ) §: Defined in CSS Speech 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
oldlace (concept) §: Defined in CSS Color 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
oldlace (CSS value for <color>, <named-color> type ) §: Defined in CSS Color 4
ToggleEvent.oldState (WebIDL attribute) §: Defined in HTML
oldstyle-nums (CSS value for font-variant-numeric ) §: Defined in CSS Fonts 4; Referenced in CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
PushSubscriptionChangeEvent.oldSubscription (WebIDL attribute) §: Defined in Push API
PushSubscriptionChangeEventInit.oldSubscription (WebIDL dictionary member) §: Defined in Push API
HashChangeEvent.oldURL (WebIDL attribute) §: Defined in HTML
MutationRecord.oldValue (WebIDL attribute) §: Defined in DOM
StorageEvent.oldValue (WebIDL attribute) §: Defined in HTML
IDBVersionChangeEvent.oldVersion (WebIDL attribute) §: Defined in Indexed DB 3.0
IDBVersionChangeEventInit.oldVersion (WebIDL dictionary member) §: Defined in Indexed DB 3.0
olive (concept) §: Defined in CSS Color 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
olive (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
olivedrab (concept) §: Defined in CSS Color 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
olivedrab (CSS value for <color>, <named-color> type ) §: Defined in CSS Color 4
"omit" (value for RequestCredentials WebIDL enumeration) §: Defined in Fetch
JsonLdOptions.omitDefault (WebIDL dictionary member) §: Defined in JSON-LD 1.1 Framing
JsonLdOptions.omitGraph (WebIDL dictionary member) §: Defined in JSON-LD 1.1 Framing
on (value for autocomplete attribute of form element ) §: Defined in HTML
on (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
on (value for autocapitalize attribute of html-global ) §: Defined in HTML
on (value for autocorrect attribute of html-global ) §: Defined in HTML
on navigate callback (concept for fenced frame config ) §: Defined in Fenced Frame; Referenced in Protected Audience
on navigate callback (concept for fenced frame config instance ) §: Defined in Fenced Frame
on network disabled promises (concept for fenced frame config instance ) §: Defined in Fenced Frame
onabort (concept for AbortSignal ) §: Defined in DOM
AbortSignal.onabort (WebIDL attribute) §: Defined in DOM
Document.onabort (WebIDL attribute) §
GlobalEventHandlers.onabort (WebIDL attribute) §
HTMLElement.onabort (WebIDL attribute) §
Window.onabort (WebIDL attribute) §: Defined in HTML
FileReader.onabort (WebIDL attribute) §: Defined in File API
IDBDatabase.onabort (WebIDL attribute) §: Defined in Indexed DB 3.0
IDBTransaction.onabort (WebIDL attribute) §: Defined in Indexed DB 3.0
SourceBuffer.onabort (WebIDL attribute) §: Defined in Media Source Extensions™
XMLHttpRequestEventTarget.onabort (WebIDL attribute) §: Defined in XMLHttpRequest
Sensor.onactivate (WebIDL attribute) §: Defined in Generic Sensor API
ServiceWorkerGlobalScope.onactivate (WebIDL attribute) §: Defined in Service Workers
SourceBufferList.onaddsourcebuffer (WebIDL attribute) §: Defined in Media Source Extensions™
AudioTrackList.onaddtrack (WebIDL attribute) §
VideoTrackList.onaddtrack (WebIDL attribute) §: Defined in HTML
MediaStream.onaddtrack (WebIDL attribute) §: Defined in Media Capture and Streams
TextTrackList.onaddtrack (WebIDL attribute) §: Defined in HTML
BluetoothDeviceEventHandlers.onadvertisementreceived (WebIDL attribute) §: Defined in Web Bluetooth
WindowEventHandlers.onafterprint (WebIDL attribute) §: Defined in HTML
Document.onanimationcancel (WebIDL attribute) §
onanimationcancel (WebIDL attribute for Document, Window ) §: Defined in CSS Animations 1
GlobalEventHandlers.onanimationcancel (WebIDL attribute) §: Defined in CSS Animations 1
Document.onanimationend (WebIDL attribute) §
onanimationend (WebIDL attribute for Document, Window ) §: Defined in CSS Animations 1
GlobalEventHandlers.onanimationend (WebIDL attribute) §: Defined in CSS Animations 1
Document.onanimationiteration (WebIDL attribute) §
onanimationiteration (WebIDL attribute for Document, Window ) §: Defined in CSS Animations 1
GlobalEventHandlers.onanimationiteration (WebIDL attribute) §: Defined in CSS Animations 1
Document.onanimationstart (WebIDL attribute) §
onanimationstart (WebIDL attribute for Document, Window ) §: Defined in CSS Animations 1
GlobalEventHandlers.onanimationstart (WebIDL attribute) §: Defined in CSS Animations 1
onappinstalled (WebIDL attribute for Window ) §: Defined in Manifest Incubations
SpeechRecognition.onaudioend (WebIDL attribute) §: Defined in Web Speech API
ScriptProcessorNode.onaudioprocess (WebIDL attribute) §
ScriptProcessorNode.onaudioprocess (WebIDL attribute) §: Defined in Web Audio API , Web Audio API 1.1
SpeechRecognition.onaudiostart (WebIDL attribute) §: Defined in Web Speech API
Document.onauxclick (WebIDL attribute) §
GlobalEventHandlers.onauxclick (WebIDL attribute) §
HTMLElement.onauxclick (WebIDL attribute) §
Window.onauxclick (WebIDL attribute) §: Defined in HTML
Bluetooth.onavailabilitychanged (WebIDL attribute) §: Defined in Web Bluetooth
ServiceWorkerGlobalScope.onbackgroundfetchabort (WebIDL attribute) §: Defined in Background Fetch
ServiceWorkerGlobalScope.onbackgroundfetchclick (WebIDL attribute) §: Defined in Background Fetch
ServiceWorkerGlobalScope.onbackgroundfetchfail (WebIDL attribute) §: Defined in Background Fetch
ServiceWorkerGlobalScope.onbackgroundfetchsuccess (WebIDL attribute) §: Defined in Background Fetch
RTCRtpScriptTransformer.onbandwidthestimate (WebIDL attribute) §: Defined in WebRTC Encoded Transform
Document.onbeforeinput (WebIDL attribute) §
GlobalEventHandlers.onbeforeinput (WebIDL attribute) §
HTMLElement.onbeforeinput (WebIDL attribute) §
Window.onbeforeinput (WebIDL attribute) §: Defined in HTML
onbeforeinstallprompt (WebIDL attribute for Window ) §: Defined in Manifest Incubations
Document.onbeforematch (WebIDL attribute) §
GlobalEventHandlers.onbeforematch (WebIDL attribute) §
HTMLElement.onbeforematch (WebIDL attribute) §
Window.onbeforematch (WebIDL attribute) §: Defined in HTML
WindowEventHandlers.onbeforeprint (WebIDL attribute) §: Defined in HTML
Document.onbeforetoggle (WebIDL attribute) §
GlobalEventHandlers.onbeforetoggle (WebIDL attribute) §
HTMLElement.onbeforetoggle (WebIDL attribute) §
Window.onbeforetoggle (WebIDL attribute) §: Defined in HTML
WindowEventHandlers.onbeforeunload (WebIDL attribute) §: Defined in HTML
OnBeforeUnloadEventHandler (WebIDL type alias) §: Defined in HTML; see also WebIDLPedia
OnBeforeUnloadEventHandlerNonNull (WebIDL callback) §: Defined in HTML
GlobalEventHandlers.onbeforexrselect (WebIDL attribute) §: Defined in WebXR DOM Overlays
onbegin (markup attribute for animate, animateMotion, animateTransform, discard, set element ) §: Defined in SVG 2
IDBOpenDBRequest.onblocked (WebIDL attribute) §: Defined in Indexed DB 3.0
GlobalEventHandlers.onblur (WebIDL attribute) §: Defined in HTML
SpeechSynthesisUtterance.onboundary (WebIDL attribute) §: Defined in Web Speech API
RTCDataChannel.onbufferedamountlow (WebIDL attribute) §: Defined in WebRTC 1.0
ManagedSourceBuffer.onbufferedchange (WebIDL attribute) §: Defined in Media Source Extensions™
Animation.oncancel (WebIDL attribute) §: Defined in Web Animations
CloseWatcher.oncancel (WebIDL attribute) §: Defined in HTML
Document.oncancel (WebIDL attribute) §
GlobalEventHandlers.oncancel (WebIDL attribute) §
HTMLElement.oncancel (WebIDL attribute) §
Window.oncancel (WebIDL attribute) §: Defined in HTML
ServiceWorkerGlobalScope.oncanmakepayment (WebIDL attribute) §: Defined in Payment Handler API
Document.oncanplay (WebIDL attribute) §
GlobalEventHandlers.oncanplay (WebIDL attribute) §
HTMLElement.oncanplay (WebIDL attribute) §
Window.oncanplay (WebIDL attribute) §: Defined in HTML
Document.oncanplaythrough (WebIDL attribute) §
GlobalEventHandlers.oncanplaythrough (WebIDL attribute) §
HTMLElement.oncanplaythrough (WebIDL attribute) §
Window.oncanplaythrough (WebIDL attribute) §: Defined in HTML
MediaDevices.oncaptureaction (WebIDL attribute) §: Defined in The Capture-Handle Actions Mechanism
CaptureController.oncapturedmousechange (WebIDL attribute) §: Defined in Captured Mouse Events
MediaStreamTrack.oncapturehandlechange (WebIDL attribute) §: Defined in Capture Handle - Bootstrapping Collaboration when Screensharing
"@once" (value for JsonLdEmbed WebIDL enumeration) §: Defined in JSON-LD 1.1 Framing
"once" (value for AnimationTriggerBehavior WebIDL enumeration) §: Defined in Web Animations 2
AddEventListenerOptions.once (WebIDL dictionary member) §: Defined in DOM; Referenced in Web Platform Design Principles
FenceEvent.once (WebIDL dictionary member) §: Defined in Fenced Frame
AudioTrackList.onchange (WebIDL attribute) §
VideoTrackList.onchange (WebIDL attribute) §: Defined in HTML
CookieStore.onchange (WebIDL attribute) §: Defined in Cookie Store API
DevicePosture.onchange (WebIDL attribute) §: Defined in Device Posture API; Referenced in CSS Viewport 1
Document.onchange (WebIDL attribute) §
GlobalEventHandlers.onchange (WebIDL attribute) §
HTMLElement.onchange (WebIDL attribute) §
Window.onchange (WebIDL attribute) §: Defined in HTML
IdleDetector.onchange (WebIDL attribute) §: Defined in Idle Detection API
MediaQueryList.onchange (WebIDL attribute) §: Defined in CSSOM View
NetworkInformation.onchange (WebIDL attribute) §: Defined in Network Information API
PermissionStatus.onchange (WebIDL attribute) §: Defined in Permissions
PreferenceObject.onchange (WebIDL attribute) §: Defined in Media Queries 5
PresentationAvailability.onchange (WebIDL attribute) §: Defined in Presentation API
Screen.onchange (WebIDL attribute) §: Defined in Window Management
ScreenDetailed.onchange (WebIDL attribute) §: Defined in Window Management
ScreenOrientation.onchange (WebIDL attribute) §: Defined in Screen Orientation; Referenced in CSS Viewport 1
TextTrackList.onchange (WebIDL attribute) §: Defined in HTML
EditContext.oncharacterboundsupdate (WebIDL attribute) §: Defined in EditContext API
CharacteristicEventHandlers.oncharacteristicvaluechanged (WebIDL attribute) §: Defined in Web Bluetooth
BatteryManager.onchargingchange (WebIDL attribute) §: Defined in Battery Status API
BatteryManager.onchargingtimechange (WebIDL attribute) §: Defined in Battery Status API
Document.onclick (WebIDL attribute) §
GlobalEventHandlers.onclick (WebIDL attribute) §
HTMLElement.onclick (WebIDL attribute) §
Window.onclick (WebIDL attribute) §: Defined in HTML
Notification.onclick (WebIDL attribute) §: Defined in Notifications API
CloseWatcher.onclose (WebIDL attribute) §: Defined in HTML
Document.onclose (WebIDL attribute) §
GlobalEventHandlers.onclose (WebIDL attribute) §
HTMLElement.onclose (WebIDL attribute) §
Window.onclose (WebIDL attribute) §: Defined in HTML
IDBDatabase.onclose (WebIDL attribute) §: Defined in Indexed DB 3.0
MessagePort.onclose (WebIDL attribute) §: Defined in HTML
Notification.onclose (WebIDL attribute) §: Defined in Notifications API
PresentationConnection.onclose (WebIDL attribute) §: Defined in Presentation API
RTCDataChannel.onclose (WebIDL attribute) §: Defined in WebRTC 1.0
WebSocket.onclose (WebIDL attribute) §: Defined in WebSockets
RTCDataChannel.onclosing (WebIDL attribute) §: Defined in WebRTC 1.0
Document.oncommand (WebIDL attribute) §
GlobalEventHandlers.oncommand (WebIDL attribute) §
HTMLElement.oncommand (WebIDL attribute) §
Window.oncommand (WebIDL attribute) §: Defined in HTML
IDBTransaction.oncomplete (WebIDL attribute) §: Defined in Indexed DB 3.0
OfflineAudioContext.oncomplete (WebIDL attribute) §
OfflineAudioContext.oncomplete (WebIDL attribute) §: Defined in Web Audio API , Web Audio API 1.1
EditContext.oncompositionend (WebIDL attribute) §: Defined in EditContext API
EditContext.oncompositionstart (WebIDL attribute) §: Defined in EditContext API
HID.onconnect (WebIDL attribute) §: Defined in WebHID API
PresentationConnection.onconnect (WebIDL attribute) §: Defined in Presentation API
RemotePlayback.onconnect (WebIDL attribute) §: Defined in Remote Playback API
Serial.onconnect (WebIDL attribute) §: Defined in Web Serial API
SerialPort.onconnect (WebIDL attribute) §: Defined in Web Serial API
SharedWorkerGlobalScope.onconnect (WebIDL attribute) §: Defined in HTML
USB.onconnect (WebIDL attribute) §: Defined in WebUSB API
RemotePlayback.onconnecting (WebIDL attribute) §: Defined in Remote Playback API
PresentationConnectionList.onconnectionavailable (WebIDL attribute) §: Defined in Presentation API
PresentationRequest.onconnectionavailable (WebIDL attribute) §: Defined in Presentation API
RTCPeerConnection.onconnectionstatechange (WebIDL attribute) §: Defined in WebRTC 1.0
ServiceWorkerGlobalScope.oncontentdelete (WebIDL attribute) §: Defined in Content Index
Document.oncontextlost (WebIDL attribute) §
GlobalEventHandlers.oncontextlost (WebIDL attribute) §
HTMLElement.oncontextlost (WebIDL attribute) §
Window.oncontextlost (WebIDL attribute) §: Defined in HTML
OffscreenCanvas.oncontextlost (WebIDL attribute) §: Defined in HTML
Document.oncontextmenu (WebIDL attribute) §
GlobalEventHandlers.oncontextmenu (WebIDL attribute) §
HTMLElement.oncontextmenu (WebIDL attribute) §
Window.oncontextmenu (WebIDL attribute) §: Defined in HTML
Document.oncontextrestored (WebIDL attribute) §
GlobalEventHandlers.oncontextrestored (WebIDL attribute) §
HTMLElement.oncontextrestored (WebIDL attribute) §
Window.oncontextrestored (WebIDL attribute) §: Defined in HTML
OffscreenCanvas.oncontextrestored (WebIDL attribute) §: Defined in HTML
ServiceWorkerContainer.oncontrollerchange (WebIDL attribute) §: Defined in Service Workers
ServiceWorkerGlobalScope.oncookiechange (WebIDL attribute) §: Defined in Cookie Store API
Document.oncopy (WebIDL attribute) §
GlobalEventHandlers.oncopy (WebIDL attribute) §
HTMLElement.oncopy (WebIDL attribute) §
Window.oncopy (WebIDL attribute) §: Defined in HTML
Document.oncuechange (WebIDL attribute) §
GlobalEventHandlers.oncuechange (WebIDL attribute) §
HTMLElement.oncuechange (WebIDL attribute) §
Window.oncuechange (WebIDL attribute) §: Defined in HTML
TextTrack.oncuechange (WebIDL attribute) §: Defined in HTML
Navigation.oncurrententrychange (WebIDL attribute) §: Defined in HTML
ScreenDetails.oncurrentscreenchange (WebIDL attribute) §: Defined in Window Management
Document.oncut (WebIDL attribute) §
GlobalEventHandlers.oncut (WebIDL attribute) §
HTMLElement.oncut (WebIDL attribute) §
Window.oncut (WebIDL attribute) §: Defined in HTML
MediaRecorder.ondataavailable (WebIDL attribute) §: Defined in MediaStream Recording
RTCPeerConnection.ondatachannel (WebIDL attribute) §: Defined in WebRTC 1.0
Document.ondblclick (WebIDL attribute) §
GlobalEventHandlers.ondblclick (WebIDL attribute) §
HTMLElement.ondblclick (WebIDL attribute) §
Window.ondblclick (WebIDL attribute) §: Defined in HTML
AudioDecoder.ondequeue (WebIDL attribute) §: Defined in WebCodecs
AudioEncoder.ondequeue (WebIDL attribute) §: Defined in WebCodecs
VideoDecoder.ondequeue (WebIDL attribute) §: Defined in WebCodecs
VideoEncoder.ondequeue (WebIDL attribute) §: Defined in WebCodecs
MediaDevices.ondevicechange (WebIDL attribute) §: Defined in Media Capture and Streams
XRSystem.ondevicechange (WebIDL attribute) §: Defined in WebXR Device API
ondevicemotion (WebIDL attribute for Window ) §: Defined in Device Orientation and Motion
ondeviceorientation (WebIDL attribute for Window ) §: Defined in Device Orientation and Motion
ondeviceorientationabsolute (WebIDL attribute for Window ) §: Defined in Device Orientation and Motion
BatteryManager.ondischargingtimechange (WebIDL attribute) §: Defined in Battery Status API
HID.ondisconnect (WebIDL attribute) §: Defined in WebHID API
RemotePlayback.ondisconnect (WebIDL attribute) §: Defined in Remote Playback API
Serial.ondisconnect (WebIDL attribute) §: Defined in Web Serial API
SerialPort.ondisconnect (WebIDL attribute) §: Defined in Web Serial API
USB.ondisconnect (WebIDL attribute) §: Defined in WebUSB API
NavigationHistoryEntry.ondispose (WebIDL attribute) §: Defined in HTML
CreateMonitor.ondownloadprogress (WebIDL attribute) §: Defined in Writing Assistance APIs
Document.ondrag (WebIDL attribute) §
GlobalEventHandlers.ondrag (WebIDL attribute) §
HTMLElement.ondrag (WebIDL attribute) §
Window.ondrag (WebIDL attribute) §: Defined in HTML
Document.ondragend (WebIDL attribute) §
GlobalEventHandlers.ondragend (WebIDL attribute) §
HTMLElement.ondragend (WebIDL attribute) §
Window.ondragend (WebIDL attribute) §: Defined in HTML
Document.ondragenter (WebIDL attribute) §
GlobalEventHandlers.ondragenter (WebIDL attribute) §
HTMLElement.ondragenter (WebIDL attribute) §
Window.ondragenter (WebIDL attribute) §: Defined in HTML
Document.ondragleave (WebIDL attribute) §
GlobalEventHandlers.ondragleave (WebIDL attribute) §
HTMLElement.ondragleave (WebIDL attribute) §
Window.ondragleave (WebIDL attribute) §: Defined in HTML
Document.ondragover (WebIDL attribute) §
GlobalEventHandlers.ondragover (WebIDL attribute) §
HTMLElement.ondragover (WebIDL attribute) §
Window.ondragover (WebIDL attribute) §: Defined in HTML
Document.ondragstart (WebIDL attribute) §
GlobalEventHandlers.ondragstart (WebIDL attribute) §
HTMLElement.ondragstart (WebIDL attribute) §
Window.ondragstart (WebIDL attribute) §: Defined in HTML
Document.ondrop (WebIDL attribute) §
GlobalEventHandlers.ondrop (WebIDL attribute) §
HTMLElement.ondrop (WebIDL attribute) §
Window.ondrop (WebIDL attribute) §: Defined in HTML
Document.ondurationchange (WebIDL attribute) §
GlobalEventHandlers.ondurationchange (WebIDL attribute) §
HTMLElement.ondurationchange (WebIDL attribute) §
Window.ondurationchange (WebIDL attribute) §: Defined in HTML
"one" (value for GPUBlendFactor WebIDL enumeration) §: Defined in WebGPU
"one-minus-constant" (value for GPUBlendFactor WebIDL enumeration) §: Defined in WebGPU
"one-minus-dst" (value for GPUBlendFactor WebIDL enumeration) §: Defined in WebGPU
"one-minus-dst-alpha" (value for GPUBlendFactor WebIDL enumeration) §: Defined in WebGPU
"one-minus-src" (value for GPUBlendFactor WebIDL enumeration) §: Defined in WebGPU
"one-minus-src-alpha" (value for GPUBlendFactor WebIDL enumeration) §: Defined in WebGPU
"one-minus-src1" (value for GPUBlendFactor WebIDL enumeration) §: Defined in WebGPU
"one-minus-src1-alpha" (value for GPUBlendFactor WebIDL enumeration) §: Defined in WebGPU
one-time-code (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; Referenced in SMS One-Time Codes
Document.onemptied (WebIDL attribute) §
GlobalEventHandlers.onemptied (WebIDL attribute) §
HTMLElement.onemptied (WebIDL attribute) §
Window.onemptied (WebIDL attribute) §: Defined in HTML
HTMLMediaElement.onencrypted (WebIDL attribute) §: Defined in Encrypted Media Extensions
onend (markup attribute for animate, animateMotion, animateTransform, discard, set element ) §: Defined in SVG 2
SpeechRecognition.onend (WebIDL attribute) §: Defined in Web Speech API
SpeechSynthesisUtterance.onend (WebIDL attribute) §: Defined in Web Speech API
XRSession.onend (WebIDL attribute) §: Defined in WebXR Device API
AudioScheduledSourceNode.onended (WebIDL attribute) §
AudioScheduledSourceNode.onended (WebIDL attribute) §: Defined in Web Audio API , Web Audio API 1.1
Document.onended (WebIDL attribute) §
GlobalEventHandlers.onended (WebIDL attribute) §
HTMLElement.onended (WebIDL attribute) §
Window.onended (WebIDL attribute) §: Defined in HTML
MediaStreamTrack.onended (WebIDL attribute) §: Defined in Media Capture and Streams
ManagedMediaSource.onendstreaming (WebIDL attribute) §: Defined in Media Source Extensions™
DocumentPictureInPicture.onenter (WebIDL attribute) §: Defined in Document Picture-in-Picture
TextTrackCue.onenter (WebIDL attribute) §: Defined in HTML
HTMLVideoElement.onenterpictureinpicture (WebIDL attribute) §: Defined in Picture-in-Picture
AbstractWorker.onerror (WebIDL attribute) §: Defined in HTML
AudioContext.onerror (WebIDL attribute) §
AudioContext.onerror (WebIDL attribute) §: Defined in Web Audio API , Web Audio API 1.1
EventSource.onerror (WebIDL attribute) §: Defined in HTML
FileReader.onerror (WebIDL attribute) §: Defined in File API
GlobalEventHandlers.onerror (WebIDL attribute) §: Defined in HTML
IDBDatabase.onerror (WebIDL attribute) §: Defined in Indexed DB 3.0
IDBRequest.onerror (WebIDL attribute) §: Defined in Indexed DB 3.0; Referenced in Writing Promise-Using Specifications
IDBTransaction.onerror (WebIDL attribute) §: Defined in Indexed DB 3.0
MediaRecorder.onerror (WebIDL attribute) §: Defined in MediaStream Recording
Notification.onerror (WebIDL attribute) §: Defined in Notifications API
RTCDataChannel.onerror (WebIDL attribute) §: Defined in WebRTC 1.0
RTCDtlsTransport.onerror (WebIDL attribute) §: Defined in WebRTC 1.0
RTCIceTransport.onerror (WebIDL attribute) §: Defined in IceTransport Extensions for WebRTC
Sensor.onerror (WebIDL attribute) §: Defined in Generic Sensor API; Referenced in Orientation Sensor
SFrameKeyManagement.onerror (WebIDL attribute) §: Defined in WebRTC Encoded Transform
SourceBuffer.onerror (WebIDL attribute) §: Defined in Media Source Extensions™
SpeechRecognition.onerror (WebIDL attribute) §: Defined in Web Speech API
SpeechSynthesisUtterance.onerror (WebIDL attribute) §: Defined in Web Speech API
WebSocket.onerror (WebIDL attribute) §: Defined in WebSockets
WorkerGlobalScope.onerror (WebIDL attribute) §: Defined in HTML
XMLHttpRequestEventTarget.onerror (WebIDL attribute) §: Defined in XMLHttpRequest
OnErrorEventHandler (WebIDL type alias) §: Defined in HTML; see also WebIDLPedia
OnErrorEventHandlerNonNull (WebIDL callback) §: Defined in HTML
TextTrackCue.onexit (WebIDL attribute) §: Defined in HTML
GlobalEventHandlers.onfencedtreeclick (WebIDL attribute) §: Defined in Fenced Frame
ServiceWorkerGlobalScope.onfetch (WebIDL attribute) §: Defined in Service Workers
Animation.onfinish (WebIDL attribute) §: Defined in Web Animations
GlobalEventHandlers.onfocus (WebIDL attribute) §: Defined in HTML
Document.onformdata (WebIDL attribute) §
GlobalEventHandlers.onformdata (WebIDL attribute) §
HTMLElement.onformdata (WebIDL attribute) §
Window.onformdata (WebIDL attribute) §: Defined in HTML
XRSession.onframeratechange (WebIDL attribute) §: Defined in WebXR Device API
Document.onfreeze (WebIDL attribute) §: Defined in Page Lifecycle
Document.onfullscreenchange (WebIDL attribute) §
Element.onfullscreenchange (WebIDL attribute) §: Defined in Fullscreen API
Document.onfullscreenerror (WebIDL attribute) §
Element.onfullscreenerror (WebIDL attribute) §: Defined in Fullscreen API
WindowEventHandlers.ongamepadconnected (WebIDL attribute) §: Defined in Gamepad
WindowEventHandlers.ongamepaddisconnected (WebIDL attribute) §: Defined in Gamepad
RTCIceTransport.ongatheringstatechange (WebIDL attribute) §: Defined in WebRTC 1.0
BluetoothDeviceEventHandlers.ongattserverdisconnected (WebIDL attribute) §: Defined in Web Bluetooth
VirtualKeyboard.ongeometrychange (WebIDL attribute) §: Defined in VirtualKeyboard API
WindowControlsOverlay.ongeometrychange (WebIDL attribute) §: Defined in Window Controls Overlay
Global.onglobalerror (WebIDL attribute) §: Defined in MiniApp Lifecycle
Global.onglobalhidden (WebIDL attribute) §: Defined in MiniApp Lifecycle
Global.ongloballaunched (WebIDL attribute) §: Defined in MiniApp Lifecycle
Global.onglobalshown (WebIDL attribute) §: Defined in MiniApp Lifecycle
Global.onglobalunloaded (WebIDL attribute) §: Defined in MiniApp Lifecycle
GlobalEventHandlers.ongotpointercapture (WebIDL attribute) §
GlobalEventHandlers.ongotpointercapture (WebIDL attribute) §: Defined in Pointer Events , Pointer Events
WindowEventHandlers.onhashchange (WebIDL attribute) §: Defined in HTML
RTCIceTransport.onicecandidate (WebIDL attribute) §: Defined in IceTransport Extensions for WebRTC
RTCPeerConnection.onicecandidate (WebIDL attribute) §: Defined in WebRTC 1.0
RTCPeerConnection.onicecandidateerror (WebIDL attribute) §: Defined in WebRTC 1.0
RTCPeerConnection.oniceconnectionstatechange (WebIDL attribute) §: Defined in WebRTC 1.0
RTCPeerConnection.onicegatheringstatechange (WebIDL attribute) §: Defined in WebRTC 1.0
Document.oninput (WebIDL attribute) §
GlobalEventHandlers.oninput (WebIDL attribute) §
HTMLElement.oninput (WebIDL attribute) §
Window.oninput (WebIDL attribute) §: Defined in HTML
HIDDevice.oninputreport (WebIDL attribute) §: Defined in WebHID API
XRSession.oninputsourceschange (WebIDL attribute) §: Defined in WebXR Device API
ServiceWorkerGlobalScope.oninstall (WebIDL attribute) §: Defined in Service Workers
Document.oninvalid (WebIDL attribute) §
GlobalEventHandlers.oninvalid (WebIDL attribute) §
HTMLElement.oninvalid (WebIDL attribute) §
Window.oninvalid (WebIDL attribute) §: Defined in HTML
MediaStreamTrack.onisolationchange (WebIDL attribute) §: Defined in Identity for WebRTC 1.0
Document.onkeydown (WebIDL attribute) §
GlobalEventHandlers.onkeydown (WebIDL attribute) §
HTMLElement.onkeydown (WebIDL attribute) §
Window.onkeydown (WebIDL attribute) §: Defined in HTML
RTCRtpScriptTransformer.onkeyframerequest (WebIDL attribute) §: Defined in WebRTC Encoded Transform
Document.onkeypress (WebIDL attribute) §
GlobalEventHandlers.onkeypress (WebIDL attribute) §
HTMLElement.onkeypress (WebIDL attribute) §
Window.onkeypress (WebIDL attribute) §: Defined in HTML; Referenced in Idle Detection API
MediaKeySession.onkeystatuseschange (WebIDL attribute) §: Defined in Encrypted Media Extensions
Document.onkeyup (WebIDL attribute) §
GlobalEventHandlers.onkeyup (WebIDL attribute) §
HTMLElement.onkeyup (WebIDL attribute) §
Window.onkeyup (WebIDL attribute) §: Defined in HTML
WindowEventHandlers.onlanguagechange (WebIDL attribute) §: Defined in HTML
WorkerGlobalScope.onlanguagechange (WebIDL attribute) §: Defined in HTML
Keyboard.onlayoutchange (WebIDL attribute) §: Defined in Keyboard Map
HTMLVideoElement.onleavepictureinpicture (WebIDL attribute) §: Defined in Picture-in-Picture
BatteryManager.onlevelchange (WebIDL attribute) §: Defined in Battery Status API
NavigatorOnLine.onLine (WebIDL attribute) §: Defined in HTML; Referenced in Network Error Logging
online (event for Window, WorkerGlobalScope interface ) §: Defined in HTML
FileReader.onload (WebIDL attribute) §: Defined in File API
GlobalEventHandlers.onload (WebIDL attribute) §: Defined in HTML; Referenced in Privacy Principles
XMLHttpRequestEventTarget.onload (WebIDL attribute) §: Defined in XMLHttpRequest
Document.onloadeddata (WebIDL attribute) §
GlobalEventHandlers.onloadeddata (WebIDL attribute) §
HTMLElement.onloadeddata (WebIDL attribute) §
Window.onloadeddata (WebIDL attribute) §: Defined in HTML
Document.onloadedmetadata (WebIDL attribute) §
GlobalEventHandlers.onloadedmetadata (WebIDL attribute) §
HTMLElement.onloadedmetadata (WebIDL attribute) §
Window.onloadedmetadata (WebIDL attribute) §: Defined in HTML
FileReader.onloadend (WebIDL attribute) §: Defined in File API
XMLHttpRequestEventTarget.onloadend (WebIDL attribute) §: Defined in XMLHttpRequest
FontFaceSet.onloading (WebIDL attribute) §: Defined in CSS Font Loading 3
FontFaceSet.onloadingdone (WebIDL attribute) §: Defined in CSS Font Loading 3
FontFaceSet.onloadingerror (WebIDL attribute) §: Defined in CSS Font Loading 3
Document.onloadstart (WebIDL attribute) §
GlobalEventHandlers.onloadstart (WebIDL attribute) §
HTMLElement.onloadstart (WebIDL attribute) §
Window.onloadstart (WebIDL attribute) §: Defined in HTML
FileReader.onloadstart (WebIDL attribute) §: Defined in File API
XMLHttpRequestEventTarget.onloadstart (WebIDL attribute) §: Defined in XMLHttpRequest
GlobalEventHandlers.onlostpointercapture (WebIDL attribute) §
GlobalEventHandlers.onlostpointercapture (WebIDL attribute) §: Defined in Pointer Events , Pointer Events
only (CSS value for color-scheme ) §: Defined in CSS Color Adjustment 1
only (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
:only-child (CSS selector) §: Defined in Selectors 3 , Selectors 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS View Transitions 1, CSS View Transitions 2
"only-if-cached" (value for RequestCache WebIDL enumeration) §: Defined in Fetch; Referenced in Loading Signed Exchanges
:only-of-type (CSS selector) §: Defined in Selectors 3 , Selectors 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
IDBKeyRange.only(value) (WebIDL operation) §: Defined in Indexed DB 3.0
NavigatorManagedData.onmanagedconfigurationchange (WebIDL attribute) §: Defined in Managed Configuration API
SpeechSynthesisUtterance.onmark (WebIDL attribute) §: Defined in Web Speech API
BroadcastChannel.onmessage (WebIDL attribute) §: Defined in HTML
EventSource.onmessage (WebIDL attribute) §: Defined in HTML
HTMLPortalElement.onmessage (WebIDL attribute) §: Defined in Portals
MediaKeySession.onmessage (WebIDL attribute) §: Defined in Encrypted Media Extensions
MessageEventTarget.onmessage (WebIDL attribute) §: Defined in HTML
PortalHost.onmessage (WebIDL attribute) §: Defined in Portals
PresentationConnection.onmessage (WebIDL attribute) §: Defined in Presentation API
RTCDataChannel.onmessage (WebIDL attribute) §: Defined in WebRTC 1.0
ServiceWorkerContainer.onmessage (WebIDL attribute) §: Defined in Service Workers
ServiceWorkerGlobalScope.onmessage (WebIDL attribute) §: Defined in Service Workers
WebSocket.onmessage (WebIDL attribute) §: Defined in WebSockets
WindowEventHandlers.onmessage (WebIDL attribute) §: Defined in HTML
BroadcastChannel.onmessageerror (WebIDL attribute) §: Defined in HTML
HTMLPortalElement.onmessageerror (WebIDL attribute) §: Defined in Portals
MessageEventTarget.onmessageerror (WebIDL attribute) §: Defined in HTML
PortalHost.onmessageerror (WebIDL attribute) §: Defined in Portals
ServiceWorkerContainer.onmessageerror (WebIDL attribute) §: Defined in Service Workers
ServiceWorkerGlobalScope.onmessageerror (WebIDL attribute) §: Defined in Service Workers
WindowEventHandlers.onmessageerror (WebIDL attribute) §: Defined in HTML
MIDIInput.onmidimessage (WebIDL attribute) §: Defined in Web MIDI API
Document.onmousedown (WebIDL attribute) §
GlobalEventHandlers.onmousedown (WebIDL attribute) §
HTMLElement.onmousedown (WebIDL attribute) §
Window.onmousedown (WebIDL attribute) §: Defined in HTML
Document.onmouseenter (WebIDL attribute) §
GlobalEventHandlers.onmouseenter (WebIDL attribute) §
HTMLElement.onmouseenter (WebIDL attribute) §
Window.onmouseenter (WebIDL attribute) §: Defined in HTML
Document.onmouseleave (WebIDL attribute) §
GlobalEventHandlers.onmouseleave (WebIDL attribute) §
HTMLElement.onmouseleave (WebIDL attribute) §
Window.onmouseleave (WebIDL attribute) §: Defined in HTML
Document.onmousemove (WebIDL attribute) §
GlobalEventHandlers.onmousemove (WebIDL attribute) §
HTMLElement.onmousemove (WebIDL attribute) §
Window.onmousemove (WebIDL attribute) §: Defined in HTML; Referenced in Idle Detection API
Document.onmouseout (WebIDL attribute) §
GlobalEventHandlers.onmouseout (WebIDL attribute) §
HTMLElement.onmouseout (WebIDL attribute) §
Window.onmouseout (WebIDL attribute) §: Defined in HTML
Document.onmouseover (WebIDL attribute) §
GlobalEventHandlers.onmouseover (WebIDL attribute) §
HTMLElement.onmouseover (WebIDL attribute) §
Window.onmouseover (WebIDL attribute) §: Defined in HTML
Document.onmouseup (WebIDL attribute) §
GlobalEventHandlers.onmouseup (WebIDL attribute) §
HTMLElement.onmouseup (WebIDL attribute) §
Window.onmouseup (WebIDL attribute) §: Defined in HTML
MediaStreamTrack.onmute (WebIDL attribute) §: Defined in Media Capture and Streams; Referenced in MediaStream Image Capture
Navigation.onnavigate (WebIDL attribute) §: Defined in HTML
Navigation.onnavigateerror (WebIDL attribute) §: Defined in HTML
Navigation.onnavigatesuccess (WebIDL attribute) §: Defined in HTML
RTCPeerConnection.onnegotiationneeded (WebIDL attribute) §: Defined in WebRTC 1.0
SpeechRecognition.onnomatch (WebIDL attribute) §: Defined in Web Speech API
ServiceWorkerGlobalScope.onnotificationclick (WebIDL attribute) §: Defined in Notifications API; Referenced in Service Workers
ServiceWorkerGlobalScope.onnotificationclose (WebIDL attribute) §: Defined in Notifications API; Referenced in Service Workers
WindowEventHandlers.onoffline (WebIDL attribute) §: Defined in HTML
WorkerGlobalScope.onoffline (WebIDL attribute) §: Defined in HTML
WindowEventHandlers.ononline (WebIDL attribute) §: Defined in HTML
WorkerGlobalScope.ononline (WebIDL attribute) §: Defined in HTML
EventSource.onopen (WebIDL attribute) §: Defined in HTML
RTCDataChannel.onopen (WebIDL attribute) §: Defined in WebRTC 1.0
WebSocket.onopen (WebIDL attribute) §: Defined in WebSockets
HTMLBodyElement.onorientationchange (WebIDL attribute) §: Defined in Compatibility
onorientationchange (WebIDL attribute for Window ) §: Defined in Compatibility
GlobalEventHandlers.onoverscroll (WebIDL attribute) §: Defined in overscroll and scrollend events
Page.onpagehidden (WebIDL attribute) §: Defined in MiniApp Lifecycle
WindowEventHandlers.onpagehide (WebIDL attribute) §: Defined in HTML
Page.onpageloaded (WebIDL attribute) §: Defined in MiniApp Lifecycle
Page.onpageready (WebIDL attribute) §: Defined in MiniApp Lifecycle
WindowEventHandlers.onpagereveal (WebIDL attribute) §: Defined in HTML
WindowEventHandlers.onpageshow (WebIDL attribute) §: Defined in HTML
Page.onpageshown (WebIDL attribute) §: Defined in MiniApp Lifecycle
WindowEventHandlers.onpageswap (WebIDL attribute) §: Defined in HTML
Page.onpageunloaded (WebIDL attribute) §: Defined in MiniApp Lifecycle
Document.onpaste (WebIDL attribute) §
GlobalEventHandlers.onpaste (WebIDL attribute) §
HTMLElement.onpaste (WebIDL attribute) §
Window.onpaste (WebIDL attribute) §: Defined in HTML
Document.onpause (WebIDL attribute) §
GlobalEventHandlers.onpause (WebIDL attribute) §
HTMLElement.onpause (WebIDL attribute) §
Window.onpause (WebIDL attribute) §: Defined in HTML
MediaRecorder.onpause (WebIDL attribute) §: Defined in MediaStream Recording
SpeechSynthesisUtterance.onpause (WebIDL attribute) §: Defined in Web Speech API
PaymentResponse.onpayerdetailchange (WebIDL attribute) §: Defined in Payment Request API
PaymentRequest.onpaymentmethodchange (WebIDL attribute) §: Defined in Payment Request API
ServiceWorkerGlobalScope.onpaymentrequest (WebIDL attribute) §: Defined in Payment Handler API
ServiceWorkerGlobalScope.onperiodicsync (WebIDL attribute) §: Defined in Web Periodic Background Synchronization
Document.onplay (WebIDL attribute) §
GlobalEventHandlers.onplay (WebIDL attribute) §
HTMLElement.onplay (WebIDL attribute) §
Window.onplay (WebIDL attribute) §: Defined in HTML
Document.onplaying (WebIDL attribute) §
GlobalEventHandlers.onplaying (WebIDL attribute) §
HTMLElement.onplaying (WebIDL attribute) §
Window.onplaying (WebIDL attribute) §: Defined in HTML
GlobalEventHandlers.onpointercancel (WebIDL attribute) §
GlobalEventHandlers.onpointercancel (WebIDL attribute) §: Defined in Pointer Events , Pointer Events
GlobalEventHandlers.onpointerdown (WebIDL attribute) §
GlobalEventHandlers.onpointerdown (WebIDL attribute) §: Defined in Pointer Events , Pointer Events
GlobalEventHandlers.onpointerenter (WebIDL attribute) §
GlobalEventHandlers.onpointerenter (WebIDL attribute) §: Defined in Pointer Events , Pointer Events
GlobalEventHandlers.onpointerleave (WebIDL attribute) §
GlobalEventHandlers.onpointerleave (WebIDL attribute) §: Defined in Pointer Events , Pointer Events
Document.onpointerlockchange (WebIDL attribute) §: Defined in Pointer Lock 2.0
Document.onpointerlockerror (WebIDL attribute) §: Defined in Pointer Lock 2.0
GlobalEventHandlers.onpointermove (WebIDL attribute) §
GlobalEventHandlers.onpointermove (WebIDL attribute) §: Defined in Pointer Events , Pointer Events
GlobalEventHandlers.onpointerout (WebIDL attribute) §
GlobalEventHandlers.onpointerout (WebIDL attribute) §: Defined in Pointer Events , Pointer Events
GlobalEventHandlers.onpointerover (WebIDL attribute) §
GlobalEventHandlers.onpointerover (WebIDL attribute) §: Defined in Pointer Events , Pointer Events
GlobalEventHandlers.onpointerrawupdate (WebIDL attribute) §
GlobalEventHandlers.onpointerrawupdate (WebIDL attribute) §: Defined in Pointer Events , Pointer Events
GlobalEventHandlers.onpointerup (WebIDL attribute) §
GlobalEventHandlers.onpointerup (WebIDL attribute) §: Defined in Pointer Events , Pointer Events
WindowEventHandlers.onpopstate (WebIDL attribute) §: Defined in HTML
onportalactivate (WebIDL attribute for Window ) §: Defined in Portals
WindowEventHandlers.onportalactivate (WebIDL attribute) §: Defined in Portals
Document.onprerenderingchange (WebIDL attribute) §: Defined in Prerendering Revamped
TaskSignal.onprioritychange (WebIDL attribute) §: Defined in Prioritized Task Scheduling
AudioWorkletNode.onprocessorerror (WebIDL attribute) §
AudioWorkletNode.onprocessorerror (WebIDL attribute) §: Defined in Web Audio API , Web Audio API 1.1
BackgroundFetchRegistration.onprogress (WebIDL attribute) §: Defined in Background Fetch
Document.onprogress (WebIDL attribute) §
GlobalEventHandlers.onprogress (WebIDL attribute) §
HTMLElement.onprogress (WebIDL attribute) §
Window.onprogress (WebIDL attribute) §: Defined in HTML
FileReader.onprogress (WebIDL attribute) §: Defined in File API
XMLHttpRequestEventTarget.onprogress (WebIDL attribute) §: Defined in XMLHttpRequest
ServiceWorkerGlobalScope.onpush (WebIDL attribute) §: Defined in Push API
ServiceWorkerGlobalScope.onpushsubscriptionchange (WebIDL attribute) §: Defined in Push API
Document.onratechange (WebIDL attribute) §
GlobalEventHandlers.onratechange (WebIDL attribute) §
HTMLElement.onratechange (WebIDL attribute) §
Window.onratechange (WebIDL attribute) §: Defined in HTML
NDEFReader.onreading (WebIDL attribute) §: Defined in Web NFC
Sensor.onreading (WebIDL attribute) §: Defined in Generic Sensor API
NDEFReader.onreadingerror (WebIDL attribute) §: Defined in Web NFC
Document.onreadystatechange (WebIDL attribute) §: Defined in HTML; Referenced in Prerendering Revamped
XMLHttpRequest.onreadystatechange (WebIDL attribute) §: Defined in XMLHttpRequest; Referenced in Writing Promise-Using Specifications
XRCubeLayer.onredraw (WebIDL attribute) §: Defined in WebXR Layers API 1
XRCylinderLayer.onredraw (WebIDL attribute) §: Defined in WebXR Layers API 1
XREquirectLayer.onredraw (WebIDL attribute) §: Defined in WebXR Layers API 1
XRQuadLayer.onredraw (WebIDL attribute) §: Defined in WebXR Layers API 1
XRLightProbe.onreflectionchange (WebIDL attribute) §: Defined in WebXR Lighting Estimation API 1
WindowEventHandlers.onrejectionhandled (WebIDL attribute) §: Defined in HTML
WorkerGlobalScope.onrejectionhandled (WebIDL attribute) §: Defined in HTML
WakeLockSentinel.onrelease (WebIDL attribute) §: Defined in Screen Wake Lock API
Animation.onremove (WebIDL attribute) §: Defined in Web Animations
SourceBufferList.onremovesourcebuffer (WebIDL attribute) §: Defined in Media Source Extensions™
AudioTrackList.onremovetrack (WebIDL attribute) §
VideoTrackList.onremovetrack (WebIDL attribute) §: Defined in HTML
MediaStream.onremovetrack (WebIDL attribute) §: Defined in Media Capture and Streams
TextTrackList.onremovetrack (WebIDL attribute) §: Defined in HTML
onrepeat (markup attribute for animate, animateMotion, animateTransform, discard, set element ) §: Defined in SVG 2
Document.onreset (WebIDL attribute) §
GlobalEventHandlers.onreset (WebIDL attribute) §
HTMLElement.onreset (WebIDL attribute) §
Window.onreset (WebIDL attribute) §: Defined in HTML
XRReferenceSpace.onreset (WebIDL attribute) §: Defined in WebXR Device API
GlobalEventHandlers.onresize (WebIDL attribute) §: Defined in HTML
PictureInPictureWindow.onresize (WebIDL attribute) §: Defined in Picture-in-Picture
VisualViewport.onresize (WebIDL attribute) §: Defined in CSSOM View
Performance.onresourcetimingbufferfull (WebIDL attribute) §: Defined in Resource Timing
SpeechRecognition.onresult (WebIDL attribute) §: Defined in Web Speech API
Document.onresume (WebIDL attribute) §: Defined in Page Lifecycle
MediaRecorder.onresume (WebIDL attribute) §: Defined in MediaStream Recording
SpeechSynthesisUtterance.onresume (WebIDL attribute) §: Defined in Web Speech API
DedicatedWorkerGlobalScope.onrtctransform (WebIDL attribute) §: Defined in WebRTC Encoded Transform
ScreenDetails.onscreenschange (WebIDL attribute) §: Defined in Window Management
GlobalEventHandlers.onscroll (WebIDL attribute) §: Defined in HTML
VisualViewport.onscroll (WebIDL attribute) §: Defined in CSSOM View
Document.onscrollend (WebIDL attribute) §
GlobalEventHandlers.onscrollend (WebIDL attribute) §
HTMLElement.onscrollend (WebIDL attribute) §
Window.onscrollend (WebIDL attribute) §: Defined in HTML
GlobalEventHandlers.onscrollend (WebIDL attribute) §: Defined in overscroll and scrollend events
VisualViewport.onscrollend (WebIDL attribute) §: Defined in CSSOM View
Document.onscrollsnapchange (WebIDL attribute) §
Element.onscrollsnapchange (WebIDL attribute) §
onscrollsnapchange (WebIDL attribute for Document, Element interface, Window ) §: Defined in CSS Scroll Snap 2
Document.onscrollsnapchanging (WebIDL attribute) §
Element.onscrollsnapchanging (WebIDL attribute) §
onscrollsnapchanging (WebIDL attribute for Document, Element interface, Window ) §: Defined in CSS Scroll Snap 2
Document.onsecuritypolicyviolation (WebIDL attribute) §
GlobalEventHandlers.onsecuritypolicyviolation (WebIDL attribute) §
HTMLElement.onsecuritypolicyviolation (WebIDL attribute) §
Window.onsecuritypolicyviolation (WebIDL attribute) §: Defined in HTML
Document.onseeked (WebIDL attribute) §
GlobalEventHandlers.onseeked (WebIDL attribute) §
HTMLElement.onseeked (WebIDL attribute) §
Window.onseeked (WebIDL attribute) §: Defined in HTML
Document.onseeking (WebIDL attribute) §
GlobalEventHandlers.onseeking (WebIDL attribute) §
HTMLElement.onseeking (WebIDL attribute) §
Window.onseeking (WebIDL attribute) §: Defined in HTML
Document.onselect (WebIDL attribute) §
GlobalEventHandlers.onselect (WebIDL attribute) §
HTMLElement.onselect (WebIDL attribute) §
Window.onselect (WebIDL attribute) §: Defined in HTML
XRSession.onselect (WebIDL attribute) §: Defined in WebXR Device API
RTCIceTransport.onselectedcandidatepairchange (WebIDL attribute) §: Defined in WebRTC 1.0
XRSession.onselectend (WebIDL attribute) §: Defined in WebXR Device API
GlobalEventHandlers.onselectionchange (WebIDL attribute) §: Defined in Selection API
GlobalEventHandlers.onselectstart (WebIDL attribute) §: Defined in Selection API
XRSession.onselectstart (WebIDL attribute) §: Defined in WebXR Device API
ServiceEventHandlers.onserviceadded (WebIDL attribute) §: Defined in Web Bluetooth
ServiceEventHandlers.onservicechanged (WebIDL attribute) §: Defined in Web Bluetooth
ServiceEventHandlers.onserviceremoved (WebIDL attribute) §: Defined in Web Bluetooth
PaymentRequest.onshippingaddresschange (WebIDL attribute) §: Defined in Payment Request API
PaymentRequest.onshippingoptionchange (WebIDL attribute) §: Defined in Payment Request API
onshow (markup attribute) §: Defined in HTML
Notification.onshow (WebIDL attribute) §: Defined in Notifications API
RTCPeerConnection.onsignalingstatechange (WebIDL attribute) §: Defined in WebRTC 1.0
AudioContext.onsinkchange (WebIDL attribute) §
AudioContext.onsinkchange (WebIDL attribute) §: Defined in Web Audio API , Web Audio API 1.1
onslotchange (concept for ShadowRoot ) §: Defined in DOM
Document.onslotchange (WebIDL attribute) §
GlobalEventHandlers.onslotchange (WebIDL attribute) §
HTMLElement.onslotchange (WebIDL attribute) §
Window.onslotchange (WebIDL attribute) §: Defined in HTML
ShadowRoot.onslotchange (WebIDL attribute) §: Defined in DOM
GlobalEventHandlers.onsnapchanged (WebIDL attribute) §: Defined in CSS Scroll Snap 2
GlobalEventHandlers.onsnapchanging (WebIDL attribute) §: Defined in CSS Scroll Snap 2
SpeechRecognition.onsoundend (WebIDL attribute) §: Defined in Web Speech API
SpeechRecognition.onsoundstart (WebIDL attribute) §: Defined in Web Speech API
MediaSource.onsourceclose (WebIDL attribute) §: Defined in Media Source Extensions™
MediaSource.onsourceended (WebIDL attribute) §: Defined in Media Source Extensions™
MediaSource.onsourceopen (WebIDL attribute) §: Defined in Media Source Extensions™
SpeechRecognition.onspeechend (WebIDL attribute) §: Defined in Web Speech API
SpeechRecognition.onspeechstart (WebIDL attribute) §: Defined in Web Speech API
XRSession.onsqueeze (WebIDL attribute) §: Defined in WebXR Device API
XRSession.onsqueezeend (WebIDL attribute) §: Defined in WebXR Device API
XRSession.onsqueezestart (WebIDL attribute) §: Defined in WebXR Device API
Document.onstalled (WebIDL attribute) §
GlobalEventHandlers.onstalled (WebIDL attribute) §
HTMLElement.onstalled (WebIDL attribute) §
Window.onstalled (WebIDL attribute) §: Defined in HTML
MediaRecorder.onstart (WebIDL attribute) §: Defined in MediaStream Recording
SpeechRecognition.onstart (WebIDL attribute) §: Defined in Web Speech API
SpeechSynthesisUtterance.onstart (WebIDL attribute) §: Defined in Web Speech API
ManagedMediaSource.onstartstreaming (WebIDL attribute) §: Defined in Media Source Extensions™
AudioSession.onstatechange (WebIDL attribute) §: Defined in Audio Session
BaseAudioContext.onstatechange (WebIDL attribute) §
BaseAudioContext.onstatechange (WebIDL attribute) §: Defined in Web Audio API , Web Audio API 1.1
MIDIAccess.onstatechange (WebIDL attribute) §: Defined in Web MIDI API
MIDIPort.onstatechange (WebIDL attribute) §: Defined in Web MIDI API
RTCDtlsTransport.onstatechange (WebIDL attribute) §: Defined in WebRTC 1.0
RTCIceTransport.onstatechange (WebIDL attribute) §: Defined in WebRTC 1.0
RTCSctpTransport.onstatechange (WebIDL attribute) §: Defined in WebRTC 1.0
ServiceWorker.onstatechange (WebIDL attribute) §: Defined in Service Workers
MediaRecorder.onstop (WebIDL attribute) §: Defined in MediaStream Recording
WindowEventHandlers.onstorage (WebIDL attribute) §: Defined in HTML
Document.onsubmit (WebIDL attribute) §
GlobalEventHandlers.onsubmit (WebIDL attribute) §
HTMLElement.onsubmit (WebIDL attribute) §
Window.onsubmit (WebIDL attribute) §: Defined in HTML
GPUQueue.onSubmittedWorkDone() (WebIDL operation) §: Defined in WebGPU
IDBRequest.onsuccess (WebIDL attribute) §: Defined in Indexed DB 3.0; Referenced in Writing Promise-Using Specifications
Document.onsuspend (WebIDL attribute) §
GlobalEventHandlers.onsuspend (WebIDL attribute) §
HTMLElement.onsuspend (WebIDL attribute) §
Window.onsuspend (WebIDL attribute) §: Defined in HTML
ServiceWorkerGlobalScope.onsync (WebIDL attribute) §: Defined in Background Sync
PresentationConnection.onterminate (WebIDL attribute) §: Defined in Presentation API
EditContext.ontextformatupdate (WebIDL attribute) §: Defined in EditContext API
EditContext.ontextupdate (WebIDL attribute) §: Defined in EditContext API
XMLHttpRequestEventTarget.ontimeout (WebIDL attribute) §: Defined in XMLHttpRequest
Document.ontimeupdate (WebIDL attribute) §
GlobalEventHandlers.ontimeupdate (WebIDL attribute) §
HTMLElement.ontimeupdate (WebIDL attribute) §
Window.ontimeupdate (WebIDL attribute) §: Defined in HTML
Document.ontoggle (WebIDL attribute) §
GlobalEventHandlers.ontoggle (WebIDL attribute) §
HTMLElement.ontoggle (WebIDL attribute) §
Window.ontoggle (WebIDL attribute) §: Defined in HTML
RTCDTMFSender.ontonechange (WebIDL attribute) §: Defined in WebRTC 1.0
GlobalEventHandlers.ontouchcancel (WebIDL attribute) §: Defined in Touch Events
GlobalEventHandlers.ontouchend (WebIDL attribute) §: Defined in Touch Events
GlobalEventHandlers.ontouchmove (WebIDL attribute) §: Defined in Touch Events
GlobalEventHandlers.ontouchstart (WebIDL attribute) §: Defined in Touch Events
RTCPeerConnection.ontrack (WebIDL attribute) §: Defined in WebRTC 1.0
GlobalEventHandlers.ontransitioncancel (WebIDL attribute) §: Defined in CSS Transitions
GlobalEventHandlers.ontransitionend (WebIDL attribute) §: Defined in CSS Transitions
GlobalEventHandlers.ontransitionrun (WebIDL attribute) §: Defined in CSS Transitions
GlobalEventHandlers.ontransitionstart (WebIDL attribute) §: Defined in CSS Transitions
GPUDevice.onuncapturederror (WebIDL attribute) §: Defined in WebGPU
WindowEventHandlers.onunhandledrejection (WebIDL attribute) §: Defined in HTML
WorkerGlobalScope.onunhandledrejection (WebIDL attribute) §: Defined in HTML
WindowEventHandlers.onunload (WebIDL attribute) §: Defined in HTML
MediaStreamTrack.onunmute (WebIDL attribute) §: Defined in Media Capture and Streams; Referenced in MediaStream Image Capture
SourceBuffer.onupdate (WebIDL attribute) §: Defined in Media Source Extensions™
SourceBuffer.onupdateend (WebIDL attribute) §: Defined in Media Source Extensions™
ServiceWorkerRegistration.onupdatefound (WebIDL attribute) §: Defined in Service Workers
SourceBuffer.onupdatestart (WebIDL attribute) §: Defined in Media Source Extensions™
IDBOpenDBRequest.onupgradeneeded (WebIDL attribute) §: Defined in Indexed DB 3.0
IDBDatabase.onversionchange (WebIDL attribute) §: Defined in Indexed DB 3.0
Document.onvisibilitychange (WebIDL attribute) §: Defined in HTML
XRSession.onvisibilitychange (WebIDL attribute) §: Defined in WebXR Device API
SpeechSynthesis.onvoiceschanged (WebIDL attribute) §: Defined in Web Speech API
Document.onvolumechange (WebIDL attribute) §
GlobalEventHandlers.onvolumechange (WebIDL attribute) §
HTMLElement.onvolumechange (WebIDL attribute) §
Window.onvolumechange (WebIDL attribute) §: Defined in HTML
Document.onwaiting (WebIDL attribute) §
GlobalEventHandlers.onwaiting (WebIDL attribute) §
HTMLElement.onwaiting (WebIDL attribute) §
Window.onwaiting (WebIDL attribute) §: Defined in HTML
HTMLMediaElement.onwaitingforkey (WebIDL attribute) §: Defined in Encrypted Media Extensions
Document.onwebkitanimationend (WebIDL attribute) §
GlobalEventHandlers.onwebkitanimationend (WebIDL attribute) §
HTMLElement.onwebkitanimationend (WebIDL attribute) §
Window.onwebkitanimationend (WebIDL attribute) §: Defined in HTML
Document.onwebkitanimationiteration (WebIDL attribute) §
GlobalEventHandlers.onwebkitanimationiteration (WebIDL attribute) §
HTMLElement.onwebkitanimationiteration (WebIDL attribute) §
Window.onwebkitanimationiteration (WebIDL attribute) §: Defined in HTML
Document.onwebkitanimationstart (WebIDL attribute) §
GlobalEventHandlers.onwebkitanimationstart (WebIDL attribute) §
HTMLElement.onwebkitanimationstart (WebIDL attribute) §
Window.onwebkitanimationstart (WebIDL attribute) §: Defined in HTML
Document.onwebkittransitionend (WebIDL attribute) §
GlobalEventHandlers.onwebkittransitionend (WebIDL attribute) §
HTMLElement.onwebkittransitionend (WebIDL attribute) §
Window.onwebkittransitionend (WebIDL attribute) §: Defined in HTML
Document.onwheel (WebIDL attribute) §
GlobalEventHandlers.onwheel (WebIDL attribute) §
HTMLElement.onwheel (WebIDL attribute) §
Window.onwheel (WebIDL attribute) §: Defined in HTML
CaptureController.onzoomlevelchange (WebIDL attribute) §: Defined in Captured Surface Control
opacity (concept) §: Defined in CSS Color 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, Largest Contentful Paint, Paint Timing
opacity (CSS property) §: Defined in CSS Color 4; Referenced in Compositing 2, Compositing 1, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Masking 1, CSS Positioned Layout 4, CSS Pseudo-Elements 4, CSS Shapes 1, CSS Table 3, CSS Transforms 2, CSS Transitions, CSS Transitions 2, CSS Typed OM 1, CSS Values 3, CSS Values 4, CSS Values 5, CSS View Transitions 1, CSS View Transitions 2, CSS Will Change 1, CSSOM View, Filter Effects 1, WebVTT: The Web Video Text Tracks Format; Related terms: CSS type <opacity-value>
XRCompositionLayer.opacity (WebIDL attribute) §: Defined in WebXR Layers API 1
<opacity-value> (CSS type for opacity ) §: Defined in CSS Color 4; Referenced in CSS Shapes 1
opacity() (CSS function for filter ) §: Defined in Filter Effects 1
CheckVisibilityOptions.opacityProperty (WebIDL dictionary member) §: Defined in CSSOM View
"opaque" (value for ResponseType WebIDL enumeration) §: Defined in Fetch
opaque (concept for visibility ) §: Defined in Fenced Frame; Referenced in Protected Audience
"opaque" (value for OpaqueProperty WebIDL enumeration) §: Defined in Fenced Frame
opaque (CSS value for environment-blending descriptor of @media @rule ) §: Defined in Media Queries 5
"opaque" (value for GPUCanvasAlphaMode WebIDL enumeration) §: Defined in WebGPU
"opaque" (value for XREnvironmentBlendMode WebIDL enumeration) §: Defined in WebXR Augmented Reality 1
opaque black (concept) §: Defined in CSS Color 4
opaque filtered response (concept) §: Defined in Fetch; Referenced in Resource Timing, Service Workers
opaque host (concept) §: Defined in URL; Referenced in WebOTP API, Web Authentication
opaque origin (concept) §: Defined in HTML; Referenced in Cookie Store API, DOM, Fetch, Topics API, Navigational-Tracking Mitigations, requestStorageAccessFor API, The Storage Access API, Storage, URL, Attribution Reporting, File System Access, User Agent Interaction with Related Website Sets, Local Font Access API, Prefetch, Shared Storage API, Protected Audience, Content Security Policy 3, Federated Credential Management API, Permissions Policy, Referrer Policy, Secure Contexts, Service Workers, Web Authentication
opaque path (concept for url ) §: Defined in URL; Referenced in HTML, URL Pattern, WebRTC 1.0
opaque path state (concept for basic URL parser ) §: Defined in URL; Referenced in URL Pattern
opaque-host parser (concept) §: Defined in URL
opaque-host-and-port string (concept) §: Defined in URL
opaque-redirect filtered response (concept) §: Defined in Fetch
OpaqueProperty (WebIDL enumeration) §: Defined in Fenced Frame; Related terms: value opaque; see also WebIDLPedia
"opaqueredirect" (value for ResponseType WebIDL enumeration) §: Defined in Fetch
:open (CSS selector) §: Defined in HTML , Selectors 4
"open" (value for ShadowRootMode WebIDL enumeration) §: Defined in DOM
open (markup attribute for details ) §: Defined in HTML; Referenced in Web Platform Design Principles, HTML Accessibility API Mappings 1.0
open (markup attribute for dialog ) §: Defined in HTML; Referenced in HTML Accessibility API Mappings 1.0
open (value for shadowrootmode attribute of template element ) §: Defined in HTML
open (event for EventSource ) §: Defined in HTML
open (event for WebSocket ) §: Defined in WebSockets
open (CSS value for bookmark-state ) §: Defined in CSS Generated Content 3
open (CSS value for text-text-emphasis ) §: Defined in CSS Text Decoration 3 , CSS Text Decoration 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
"open" (value for ReadyState WebIDL enumeration) §: Defined in Media Source Extensions™
"open" (value for MIDIPortConnectionState WebIDL enumeration) §: Defined in Web MIDI API
"open" (value for RTCDataChannelState WebIDL enumeration) §: Defined in WebRTC 1.0
open (event for RTCDataChannel ) §: Defined in WebRTC 1.0
HTMLDetailsElement.open (WebIDL attribute) §: Defined in HTML
HTMLDialogElement.open (WebIDL attribute) §: Defined in HTML
EventSource.OPEN (WebIDL constant) §: Defined in HTML
WebSocket.OPEN (WebIDL constant) §: Defined in WebSockets
open an async sequence (concept) §: Defined in Web IDL
open-quote (CSS value for <content-list>, <quote> type, content property ) §: Defined in CSS Generated Content 3; Referenced in CSS Containment 2
open-quote (CSS value for content ) §: Defined in CSS 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2025
EyeDropper.open() (WebIDL operation) §: Defined in EyeDropper API
HIDDevice.open() (WebIDL operation) §: Defined in WebHID API
MIDIPort.open() (WebIDL operation) §: Defined in Web MIDI API
SerialPort.open() (WebIDL operation) §: Defined in Web Serial API
USBDevice.open() (WebIDL operation) §: Defined in WebUSB API
CacheStorage.open(cacheName) (WebIDL operation) §: Defined in Service Workers
XMLHttpRequest.open(method, url, async, username, password) (WebIDL operation) §: Defined in XMLHttpRequest
XMLHttpRequest.open(method, url) (WebIDL operation) §: Defined in XMLHttpRequest
StorageBucketManager.open(name, options) (WebIDL operation) §: Defined in Storage Buckets API
IDBFactory.open(name, version) (WebIDL operation) §: Defined in Indexed DB 3.0
Document.open(unused1, unused2) (WebIDL operation) §: Defined in HTML
Document.open(url, name, features) (WebIDL operation) §: Defined in HTML
Window.open(url, target, features) (WebIDL operation) §: Defined in HTML; Referenced in Capability Delegation, Document Picture-in-Picture, Prerendering Revamped, CSSOM View, Web Platform Design Principles, Window Management
IDBIndex.openCursor(query, direction) (WebIDL operation) §: Defined in Indexed DB 3.0
IDBObjectStore.openCursor(query, direction) (WebIDL operation) §: Defined in Indexed DB 3.0
HIDDevice.opened (WebIDL attribute) §: Defined in WebHID API
TCPServerSocket.opened (WebIDL attribute) §: Defined in Direct Sockets API
TCPSocket.opened (WebIDL attribute) §: Defined in Direct Sockets API
UDPSocket.opened (WebIDL attribute) §: Defined in Direct Sockets API
USBDevice.opened (WebIDL attribute) §: Defined in WebUSB API
XMLHttpRequest.OPENED (WebIDL constant) §: Defined in XMLHttpRequest
opener (value for rel attribute of a, rel attribute of area element, rel attribute of form element ) §: Defined in HTML
Window.opener (WebIDL attribute) §: Defined in HTML; Referenced in Fenced Frame
opener browsing context (concept) §: Defined in HTML; Referenced in Document Picture-in-Picture, Prerendering Revamped
OpenFilePickerOptions (WebIDL dictionary) §: Defined in File System Access; Related terms: OpenFilePickerOptions.multiple; see also WebIDLPedia
IDBIndex.openKeyCursor(query, direction) (WebIDL operation) §: Defined in Indexed DB 3.0
IDBObjectStore.openKeyCursor(query, direction) (WebIDL operation) §: Defined in Indexed DB 3.0
<opentype-tag> (CSS type) §: Defined in CSS Fonts 4
PaymentRequestEvent.openWindow() (WebIDL operation) §: Defined in Payment Handler API
Clients.openWindow(url) (WebIDL operation) §: Defined in Service Workers; Referenced in Page Lifecycle
OperatingPointSelectorProperty (concept) §: Defined in AVIF; Related terms: concept a1op
operation (concept) §: Defined in Web IDL; Referenced in URL Pattern, Isolated Contexts
GPUBlendComponent.operation (WebIDL dictionary member) §: Defined in WebGPU
PrivateToken.operation (WebIDL dictionary member) §: Defined in Private State Token API
operation name (concept for saved query map ) §: Defined in Shared Storage API
OperationError (exception) §: Defined in Web IDL; Referenced in IceTransport Extensions for WebRTC, Translator and Language Detector APIs, Writing Assistance APIs, Digital Goods API, EyeDropper API, Handwriting Recognition API, Shared Storage API, Modern Algorithms in the Web Cryptography API, Secure Curves in the Web Cryptography API, MediaStream Image Capture, Payment Handler API, Presentation API, Remote Playback API, Web Cryptography 2, WebGPU, Web Neural Network API, SVC, WebRTC 1.0, WebXR Hit Test, WebXR Device API, WebXR Layers API 1
OperationType (WebIDL enumeration) §: Defined in Private State Token API; Related terms: value send-redemption-record, value token-redemption, value token-request; see also WebIDLPedia
MLOperand.[[operator]] (internal slot) §: Defined in Web Neural Network API
operator (markup attribute for feComposite ) §: Defined in Filter Effects 1; Related terms: value arithmetic, value atop, value in, value lighter, value out, value over, value xor
operator (markup attribute for feMorphology ) §: Defined in Filter Effects 1
CSSMathClamp.operator (WebIDL attribute) §
CSSMathInvert.operator (WebIDL attribute) §
CSSMathMax.operator (WebIDL attribute) §
CSSMathMin.operator (WebIDL attribute) §
CSSMathNegate.operator (WebIDL attribute) §
CSSMathProduct.operator (WebIDL attribute) §
CSSMathSum.operator (WebIDL attribute) §
CSSMathValue.operator (WebIDL attribute) §: Defined in CSS Typed OM 1
SVGFECompositeElement.operator (WebIDL attribute) §: Defined in Filter Effects 1
SVGFEMorphologyElement.operator (WebIDL attribute) §: Defined in Filter Effects 1
operator nodes (concept for calculation tree ) §: Defined in CSS Values 4
MLContext.opSupportLimits() (WebIDL operation) §: Defined in Web Neural Network API
optgroup (markup element) §: Defined in HTML; Referenced in HTML Accessibility API Mappings 1.0, ARIA in HTML, WebDriver; Related terms: markup attribute disabled, markup attribute label
optimal viewing region (concept) §: Defined in CSS Scroll Snap 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Spatial Navigation 1, CSS Scroll Anchoring 1
:optimal-value (CSS selector) §: Defined in CSS Form Control Styling 1
VideoDecoderConfig.optimizeForLatency (WebIDL dictionary member) §: Defined in WebCodecs
"optimizeLegibility" (value for CanvasTextRendering WebIDL enumeration) §: Defined in HTML
"optimizeSpeed" (value for CanvasTextRendering WebIDL enumeration) §: Defined in HTML
optimum (markup attribute for meter ) §: Defined in HTML; Referenced in HTML Accessibility API Mappings 1.0, WAI-ARIA, WAI-ARIA
HTMLMeterElement.optimum (WebIDL attribute) §: Defined in HTML
option (markup element) §: Defined in HTML; Referenced in CSS Lists 3, CSS User Interface 4, Web Platform Design Principles, HTML Accessibility API Mappings 1.0, ARIA in HTML, Selectors 4, WAI-ARIA, WAI-ARIA, WebDriver; Related terms: markup attribute disabled, markup attribute label, markup attribute name, markup attribute selected, markup attribute value
option-expression (grammar) §: Defined in SRI
new Option(text, value, defaultSelected, selected) (WebIDL constructor) §: Defined in HTML
:optional (CSS selector) §: Defined in Selectors 4
optional (concept for dictionary member ) §: Defined in Web IDL
"optional" (value for CredentialMediationRequirement WebIDL enumeration) §: Defined in Credential Management 1
optional (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
"optional" (value for MediaKeysRequirement WebIDL enumeration) §: Defined in Encrypted Media Extensions
optional argument (concept) §: Defined in Web IDL; Related terms: concept default value
optional-ascii-whitespace (grammar) §: Defined in Content Security Policy 3
OptionalEffectTiming (WebIDL dictionary) §: Defined in Web Animations; Referenced in Web Animations 2; Related terms: undefineddelay, OptionalEffectTiming.direction, undefinedduration, OptionalEffectTiming.easing, undefinedendDelay, OptionalEffectTiming.fill, OptionalEffectTiming.iterations, OptionalEffectTiming.iterationStart, OptionalEffectTiming.playbackRate; see also WebIDLPedia
XRPermissionDescriptor.optionalFeatures (WebIDL dictionary member) §: Defined in WebXR Device API; Referenced in WebXR Layers API 1
XRSessionInit.optionalFeatures (WebIDL dictionary member) §: Defined in WebXR Device API; Referenced in WebXR Depth Sensing, WebXR DOM Overlays
optionality values (concept) §: Defined in Web IDL
BluetoothPermissionDescriptor.optionalManufacturerData (WebIDL dictionary member) §: Defined in Web Bluetooth
RequestDeviceOptions.optionalManufacturerData (WebIDL dictionary member) §: Defined in Web Bluetooth
BluetoothPermissionDescriptor.optionalServices (WebIDL dictionary member) §: Defined in Web Bluetooth
RequestDeviceOptions.optionalServices (WebIDL dictionary member) §: Defined in Web Bluetooth
PaymentRequest.[[options]] (internal slot) §: Defined in Payment Request API
options (concept for cache batch operation ) §: Defined in Service Workers
HTMLDataListElement.options (WebIDL attribute) §: Defined in HTML
HTMLSelectElement.options (WebIDL attribute) §: Defined in HTML
PushSubscription.options (WebIDL attribute) §: Defined in Push API
RTCRtpScriptTransformer.options (WebIDL attribute) §: Defined in WebRTC Encoded Transform
OptOutError (exception) §: Defined in Web IDL; Referenced in Secure Payment Confirmation
"opus" (value for OpusBitstreamFormat WebIDL enumeration) §: Defined in Opus WebCodecs Registration
AudioEncoderConfig.opus (WebIDL dictionary member) §: Defined in Opus WebCodecs Registration
OpusApplication (WebIDL enumeration) §: Defined in Opus WebCodecs Registration; Related terms: value audio, value lowdelay, value voip; see also WebIDLPedia
OpusBitstreamFormat (WebIDL enumeration) §: Defined in Opus WebCodecs Registration; Related terms: value ogg, value opus; see also WebIDLPedia
OpusEncoderConfig (WebIDL dictionary) §: Defined in Opus WebCodecs Registration; Related terms: OpusEncoderConfig.application, OpusEncoderConfig.complexity, OpusEncoderConfig.format, OpusEncoderConfig.frameDuration, OpusEncoderConfig.packetlossperc, OpusEncoderConfig.signal, OpusEncoderConfig.usedtx, OpusEncoderConfig.useinbandfec; see also WebIDLPedia
OpusSignal (WebIDL enumeration) §: Defined in Opus WebCodecs Registration; Related terms: value auto, value music, value voice; see also WebIDLPedia
RouterCondition.or (WebIDL dictionary member) §: Defined in Service Workers
Atomics.or(typedArray, index, value) (WebIDL operation) §: Defined in ECMAScript
orange (concept) §: Defined in CSS Color 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
orange (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
orangered (concept) §: Defined in CSS Color 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
orangered (CSS value for <color>, <named-color> type ) §: Defined in CSS Color 4
orchid (concept) §: Defined in CSS Color 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
orchid (CSS value for <color>, <named-color> type ) §: Defined in CSS Color 4
order (CSS property) §: Defined in CSS Display 3 , CSS Display 4; Referenced in Compatibility, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Flexbox 1, CSS Lists 3, CSS Typed OM 1
order (markup attribute for feConvolveMatrix ) §: Defined in Filter Effects 1
order-modified document order (concept) §: 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
JsonLdOptions.ordered (WebIDL dictionary member) §: Defined in JSON-LD 1.1 Processing Algorithms and API
RTCDataChannel.ordered (WebIDL attribute) §: Defined in WebRTC 1.0
RTCDataChannelInit.ordered (WebIDL dictionary member) §: Defined in WebRTC 1.0
ordered map (concept) §: Defined in Infra; Referenced in Console, DOM, HTML, WebXR Body Tracking 1, MIME Sniffing, Private Aggregation API, Topics API, Navigational-Tracking Mitigations, Storage, URL Pattern, Login Status API, AT Driver, Network Reporting 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, Writing Assistance APIs, Attribution Reporting, Background Fetch, Capability Delegation, Client Hints Infrastructure, Content Index, Fenced Frame, File System Access, User Agent Interaction with Related Website Sets, Get Installed Related Apps API, Isolated Contexts, Manifest Incubations, Prefetch, Prerendering Revamped, Web Periodic Background Synchronization, HTML Sanitizer API, Prioritized Task Scheduling, Web Serial API, Shared Storage API, Signature-based Integrity, Soft Navigations, Private State Token API, Protected Audience, Web App Launch Handler API, Managed Configuration API, WebHID API, Loading Signed Exchanges, Accelerometer, Ambient Light Sensor, Web Application Manifest, Controlled Identifiers v1.0, Compute Pressure 1, Contact Picker API, Content Security Policy 3, CSS Animation Worklet API, CSS Layout API 1, CSS Painting API 1, CSS Typed OM 1, CSS View Transitions 1, CSS View Transitions 2, CSSOM View, Device Bound Session Credentials, DIDs, Event Timing API, Federated Credential Management API, File API, Gamepad, Generic Sensor API, Geolocation Sensor, Geolocation, Gyroscope, Image Resource, JSON-LD 1.1 Processing Algorithms and API, JSON-LD 1.1 Framing, JSON-LD 1.1, Largest Contentful Paint, Magnetometer, Media Capture and Streams, MiniApp Manifest, MiniApp Packaging, Device Orientation and Motion, Orientation Sensor, Payment Method Manifest, Performance Timeline, Permissions Policy, Privacy-Preserving Attribution 1, Proximity Sensor, Publication Manifest, Push API, RDF Dataset Canonicalization, RDF 1.2 Concepts and Abstract Data Model, Screen Wake Lock API, Server Timing, Service Workers, Bitstring Status List v1.0, Verifiable Credential Data Integrity 1.0, Verifiable Credentials Data Model v2.0, Data Integrity BBS Cryptosuites v1.0, Data Integrity ECDSA Cryptosuites v1.0, Data Integrity EdDSA Cryptosuites v1.0, WebAssembly JavaScript Interface, Web Locks API, Web Audio API, Web Audio API 1.1, Web Authentication, WebCodecs, WebDriver BiDi, WebDriver, WebGPU, WebRTC 1.0, WebXR Hand Input 1
ordered set (concept) §: Defined in Infra; Referenced in Cookie Store API, DOM, Fetch, File System, Fullscreen API, HTML, MIME Sniffing, Private Aggregation API, Navigational-Tracking Mitigations, Storage, Streams, AT Driver, Element Timing API, Web NFC, Web Bluetooth, Web IDL, Translator and Language Detector APIs, Writing Assistance APIs, Attribution Reporting, Client Hints Infrastructure, Fenced Frame, Get Installed Related Apps API, Prefetch, Observable, Facilitated Payment Link Type in HTML, Measure Memory API, HTML Sanitizer API, Prioritized Task Scheduling, Signature-based Integrity, Soft Navigations, Protected Audience, Web Smart Card API, WebHID API, WebUSB API, Web Application Manifest, Badging API, Controlled Identifiers v1.0, Compute Pressure 1, Credential Management 1, Content Security Policy: Embedded Enforcement, Content Security Policy 3, CSS Grid Layout 1, CSS Grid Layout 2, CSS Lists 3, CSS Spatial Navigation 1, CSS Positioned Layout 4, CSS Shadow Parts, CSS View Transitions 1, CSS View Transitions 2, DIDs, Federated Credential Management API, Generic Sensor API, Indexed DB 3.0, Largest Contentful Paint, Media Capture and Streams, Paint Timing, Payment Method Manifest, Payment Request API, Publication Manifest, Reporting API, Screen Orientation, Selectors 4, Service Workers, SRI, Trusted Types, Verifiable Credential Data Integrity 1.0, Verifiable Credentials Data Model v2.0, Web Animations, Web Locks API, Web Authentication, WebDriver BiDi, WebDriver, WebGPU, Web Neural Network API, WebRTC 1.0, WebTransport, WebXR Device API
ordered set parser (concept) §: Defined in DOM
ordered set serializer (concept) §: Defined in DOM
XPathResult.ORDERED_NODE_ITERATOR_TYPE (WebIDL constant) §: Defined in DOM
XPathResult.ORDERED_NODE_SNAPSHOT_TYPE (WebIDL constant) §: Defined in DOM; Referenced in WebDriver BiDi
SVGFEConvolveMatrixElement.orderX (WebIDL attribute) §: Defined in Filter Effects 1
SVGFEConvolveMatrixElement.orderY (WebIDL attribute) §: Defined in Filter Effects 1
ordinal (CSS value for font-variant-numeric ) §: Defined in CSS Fonts 4; Referenced in CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
ordinary object (concept for ECMAScript ) §: Defined in ECMAScript; Referenced in ECMAScript® 2026 Internationalization API, ECMAScript Async Explicit Resource Management, Deferred Imports Evaluation, ECMAScript Explicit Resource Management, Intl.DurationFormat, Intl Locale Info, JSON.parse source text access, ShadowRealm API, Source Phase Imports, Temporal
OrdinaryCallBindThis (algorithm) §: Defined in ECMAScript
OrdinaryCallEvaluateBody (algorithm) §: Defined in ECMAScript
OrdinaryCreateFromConstructor (algorithm) §: Defined in ECMAScript; Referenced in ECMAScript® 2026 Internationalization API, ECMAScript Async Explicit Resource Management, Time Zone Canonicalization, ECMAScript Explicit Resource Management, Intl.DurationFormat, Intl Locale Info, ShadowRealm API, Temporal
OrdinaryDefineOwnProperty (algorithm) §: Defined in ECMAScript; Referenced in HTML, Deferred Imports Evaluation, Web IDL
OrdinaryDelete (algorithm) §: Defined in ECMAScript; Referenced in HTML, Deferred Imports Evaluation
OrdinaryFunctionCreate (algorithm) §: Defined in ECMAScript; Referenced in HTML, ECMAScript Async Explicit Resource Management, ECMAScript Explicit Resource Management
OrdinaryGet (algorithm) §: Defined in ECMAScript; Referenced in HTML, Deferred Imports Evaluation
OrdinaryGetOwnProperty (algorithm) §: Defined in ECMAScript; Referenced in HTML, Deferred Imports Evaluation, Web IDL
OrdinaryGetPrototypeOf (algorithm) §: Defined in ECMAScript; Referenced in HTML
OrdinaryHasInstance (algorithm) §: Defined in ECMAScript; Referenced in ECMAScript® 2026 Internationalization API
OrdinaryHasProperty (algorithm) §: Defined in ECMAScript; Referenced in Deferred Imports Evaluation
OrdinaryIsExtensible (algorithm) §: Defined in ECMAScript; Referenced in HTML
OrdinaryObjectCreate (algorithm) §: Defined in ECMAScript; Referenced in Streams, ECMAScript® 2026 Internationalization API, Uint8Array to/from base64, ECMAScript Async Explicit Resource Management, ECMAScript Explicit Resource Management, Intl.DurationFormat, Intl Locale Info, JSON.parse source text access, Temporal, WebAssembly JavaScript Interface: Content Security Policy, WebAssembly JavaScript Interface: Exception Handling, WebAssembly JavaScript Interface: Promise Integration, WebAssembly JavaScript Interface: JS String Builtins, Web IDL, WebAssembly JavaScript Interface
OrdinaryOwnPropertyKeys (algorithm) §: Defined in ECMAScript; Referenced in HTML, Deferred Imports Evaluation, Web IDL
OrdinaryPreventExtensions (algorithm) §: Defined in ECMAScript; Referenced in HTML
OrdinarySet (algorithm) §: Defined in ECMAScript; Referenced in HTML
OrdinarySetPrototypeOf (algorithm) §: Defined in ECMAScript; Referenced in HTML, Web IDL
OrdinarySetWithOwnDescriptor (algorithm) §: Defined in ECMAScript; Referenced in Web IDL
OrdinaryToPrimitive (algorithm) §: Defined in ECMAScript
organization (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
organization (concept for physical address ) §: Defined in Contact Picker API
AddressErrors.organization (WebIDL dictionary member) §: Defined in Payment Request API
ContactAddress.organization (WebIDL attribute) §: Defined in Contact Picker API
organization-title (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
orient (markup attribute for marker ) §: Defined in SVG 2
SVGMarkerElement.orient (WebIDL attribute) §: Defined in SVG 2
SVGMarkerElement.orientAngle (WebIDL attribute) §: Defined in SVG 2
orientation (concept for manifest ) §: Defined in Web Application Manifest
orientation (CSS descriptor for @container ) §: Defined in CSS Conditional 5; Related terms: CSS value landscape, CSS value portrait
orientation (CSS descriptor for @media ) §: Defined in Media Queries 4 , Media Queries 5; Referenced in CSSOM; Related terms: CSS value landscape, CSS value portrait
GamepadPose.orientation (WebIDL attribute) §: Defined in Gamepad Extensions
Screen.orientation (WebIDL attribute) §: Defined in Screen Orientation
orientation (WebIDL attribute for Window ) §: Defined in Compatibility
XRCubeLayer.orientation (WebIDL attribute) §: Defined in WebXR Layers API 1
XRCubeLayerInit.orientation (WebIDL dictionary member) §: Defined in WebXR Layers API 1
XRPlane.orientation (WebIDL attribute) §: Defined in WebXR Plane Detection
XRRigidTransform.orientation (WebIDL attribute) §: Defined in WebXR Device API; Referenced in WebXR Layers API 1
OrientationLockType (WebIDL enumeration) §: Defined in Screen Orientation; Related terms: value any, value landscape, value landscape-primary, value landscape-secondary, value natural, value portrait, value portrait-primary, value portrait-secondary; see also WebIDLPedia
OrientationSensor (WebIDL interface) §: Defined in Orientation Sensor; Related terms: OrientationSensor.quaternion, OrientationSensor.populateMatrix(targetMatrix); see also WebIDLPedia
OrientationSensorLocalCoordinateSystem (WebIDL enumeration) §: Defined in Orientation Sensor; Related terms: value device, value screen; see also WebIDLPedia
OrientationSensorOptions (WebIDL dictionary) §: Defined in Orientation Sensor; Related terms: OrientationSensorOptions.referenceFrame; see also WebIDLPedia
OrientationType (WebIDL enumeration) §: Defined in Screen Orientation; Related terms: value landscape-primary, value landscape-secondary, value portrait-primary, value portrait-secondary; see also WebIDLPedia
PannerNode.orientationX (WebIDL attribute) §
PannerNode.orientationX (WebIDL attribute) §: Defined in Web Audio API , Web Audio API 1.1
PannerOptions.orientationX (WebIDL dictionary member) §
PannerOptions.orientationX (WebIDL dictionary member) §: Defined in Web Audio API , Web Audio API 1.1
PannerNode.orientationY (WebIDL attribute) §
PannerNode.orientationY (WebIDL attribute) §: Defined in Web Audio API , Web Audio API 1.1
PannerOptions.orientationY (WebIDL dictionary member) §
PannerOptions.orientationY (WebIDL dictionary member) §: Defined in Web Audio API , Web Audio API 1.1
PannerNode.orientationZ (WebIDL attribute) §
PannerNode.orientationZ (WebIDL attribute) §: Defined in Web Audio API , Web Audio API 1.1
PannerOptions.orientationZ (WebIDL dictionary member) §
PannerOptions.orientationZ (WebIDL dictionary member) §: Defined in Web Audio API , Web Audio API 1.1
SVGMarkerElement.orientType (WebIDL attribute) §: Defined in SVG 2
Credential.[[origin]] (internal slot) §: Defined in Credential Management 1
origin (concept for Document ) §: Defined in DOM; Referenced in Fetch, HTML, Topics API, Navigational-Tracking Mitigations, requestStorageAccessFor API, The Storage Access API, Login Status API, Long Animation Frames API, Document Picture-in-Picture, Fenced Frame, Prefetch, Prerendering Revamped, Portals, URL Fragment Text Directives, Shared Storage API, SMS One-Time Codes, Content Security Policy 3, CSS View Transitions 2, Federated Credential Management API, Media Queries 5, Mixed Content, Permissions Policy, Picture-in-Picture, Referrer Policy, WebDriver BiDi, XMLHttpRequest
origin (concept for request ) §: Defined in Fetch; Referenced in HTML, Navigational-Tracking Mitigations, Login Status API, Attribution Reporting, Fenced Frame, Isolated Contexts, Local Network Access, Prefetch, Shared Storage API, Protected Audience, Beacon, Content Security Policy: Embedded Enforcement, Content Security Policy 3, CSS Values 4, CSSOM, Device Bound Session Credentials, Federated Credential Management API, Fetch Metadata, Permissions Policy, Service Workers, WebTransport
origin (concept) §: Defined in HTML; Referenced in The No-Vary-Search HTTP Response Header Field, DOM, Fetch, Notifications API, Private Aggregation API, requestStorageAccessFor API, Extending Storage Access API to non-cookie storage, The Storage Access API, Storage, URL, Login Status API, Web NFC, Attribution Reporting, Fenced Frame, File System Access, User Agent Interaction with Related Website Sets, Local Font Access API, Manifest Incubations, Prefetch, Prerendering Revamped, URL Fragment Text Directives, Accelerated Shape Detection in Images, Shared Storage API, Private State Token API, Protected Audience, Web Smart Card API, Loading Signed Exchanges, Web Application Manifest, Badging API, Compute Pressure 1, Content Security Policy 3, CSS Spatial Navigation 1, CSSOM, Device Bound Session Credentials, Encrypted Media Extensions, Federated Credential Management API, Geolocation, Indexed DB 3.0, Media Capabilities, Media Source Extensions™, Network Error Logging, Payment Handler API, Payment Method Manifest, Payment Request API, Permissions, Privacy-Preserving Attribution 1, Privacy Principles, Push API, Referrer Policy, Secure Contexts, Secure Payment Confirmation, Selectors 4, Service Workers, SRI, WebTransport; Related terms: concept domain, concept host, concept port, concept scheme
origin (concept for environment settings object ) §: Defined in HTML; Referenced in Cookie Store API, Fetch, File System, Notifications API, Private Aggregation API, requestStorageAccessFor API, The Storage Access API, Storage, URL, Login Status API, Iframe credentialless, Background Fetch, Client Hints Infrastructure, Content Index, Scripting Policy, Fenced Frame, File System Access, User Agent Interaction with Related Website Sets, Isolated Contexts, Prerendering Revamped, Measure Memory API, Portals, Shared Storage API, Storage Buckets API, Protected Audience, WebOTP API, Beacon, Clear Site Data, Contact Picker API, Credential Management 1, Content Security Policy 3, CSS Values 4, Federated Credential Management API, File API, Generic Sensor API, Long Tasks API, Mixed Content, Permissions, Privacy-Preserving Attribution 1, Secure Payment Confirmation, Service Workers, Web Authentication, WebDriver BiDi, WebRTC 1.0, WebTransport, XMLHttpRequest
origin (markup attribute for animate ) §: Defined in SVG Animations 2; Referenced in SVG 2
origin (concept for url ) §: Defined in URL; Referenced in Cookie Store API, Fetch, HTML, Private Aggregation API, Topics API, requestStorageAccessFor API, The Storage Access API, Storage, Web Share Target API, WebSockets, Iframe credentialless, Attribution Reporting, Background Fetch, Client Hints Infrastructure, Content Index, Scripting Policy, Fenced Frame, User Agent Interaction with Related Website Sets, Manifest Incubations, Prefetch, Prerendering Revamped, Shared Storage API, Private State Token API, Protected Audience, Managed Configuration API, Loading Signed Exchanges, Web Application Manifest, A Well-Known URL for Changing Passwords, Clear Site Data, Content Security Policy: Embedded Enforcement, Content Security Policy 3, Device Bound Session Credentials, Federated Credential Management API, Fetch Metadata, Payment Handler API, Payment Method Manifest, Permissions Policy, Push API, Referrer Policy, Reporting API, Secure Contexts, Secure Payment Confirmation, Service Workers
origin (concept for exfiltration budget metadata ) §: Defined in Fenced Frame
origin (concept for exfiltration budget metadata reference ) §: Defined in Fenced Frame
origin (CSS value for <request-url-modifier> ) §: Defined in CSS Values 5
"origin" (value for ReferrerPolicy WebIDL enumeration) §: Defined in Referrer Policy
origin (concept) §: Defined in Referrer Policy
origin (concept for service worker client ) §: Defined in Service Workers; Referenced in Web Periodic Background Synchronization
Origin: (HTTP header) §: Defined in Fetch; Referenced in HTML, requestStorageAccessFor API, Web Application Manifest, Content Security Policy: Embedded Enforcement, Federated Credential Management API, WebTransport
CaptureHandle.origin (WebIDL dictionary member) §: Defined in Capture Handle - Bootstrapping Collaboration when Screensharing
client.origin (WebIDL attribute) §: Defined in Network Reporting API
CollectedClientData.origin (WebIDL dictionary member) §: Defined in Web Authentication; Referenced in Secure Payment Confirmation
ExtendableMessageEvent.origin (WebIDL attribute) §: Defined in Service Workers
ExtendableMessageEventInit.origin (WebIDL dictionary member) §: Defined in Service Workers
FederatedCredentialInit.origin (WebIDL dictionary member) §: Defined in Credential Management 1
GPUCopyExternalImageSourceInfo.origin (WebIDL dictionary member) §: Defined in WebGPU
GPUTexelCopyTextureInfo.origin (WebIDL dictionary member) §: Defined in WebGPU
HTMLHyperlinkElementUtils.origin (WebIDL attribute) §: Defined in HTML
Location.origin (WebIDL attribute) §: Defined in HTML
MessageEvent.origin (WebIDL attribute) §: Defined in HTML; Referenced in WebSockets, Portals, Service Workers
MessageEventInit.origin (WebIDL dictionary member) §: Defined in HTML
PasswordCredentialData.origin (WebIDL dictionary member) §: Defined in Credential Management 1
origin (WebIDL attribute for URL ) §: Defined in URL; Referenced in Get Installed Related Apps API
WindowOrWorkerGlobalScope.origin (WebIDL attribute) §: Defined in HTML
WorkerLocation.origin (WebIDL attribute) §: Defined in HTML
XRRay.origin (WebIDL attribute) §: Defined in WebXR Hit Test
origin bound (concept for Credential ) §: Defined in Credential Management 1
origin integrity verification map (concept) §: Defined in Isolated Contexts
Origin-Agent-Cluster: (HTTP header) §: Defined in HTML
origin-bound one-time code (concept) §: Defined in SMS One-Time Codes
origin-bound one-time code message (concept) §: Defined in SMS One-Time Codes; Referenced in WebOTP API
origin-when-cross-origin (CSS value for <request-url-modifier> ) §: Defined in CSS Values 5
"origin-when-cross-origin" (value for ReferrerPolicy WebIDL enumeration) §: Defined in Referrer Policy
origin-when-cross-origin (concept) §: Defined in Referrer Policy; Referenced in HTML
Window.originAgentCluster (WebIDL attribute) §: Defined in HTML
original containing block (concept) §: Defined in CSS Positioned Layout 3; Referenced in CSS Box Alignment 3, CSS Anchor Positioning
original source (concept) §: Defined in Source map format
originally specified color space (concept) §: Defined in CSS Color 5
CSPViolationReportBody.originalPolicy (WebIDL dictionary member) §: Defined in Content Security Policy 3
SecurityPolicyViolationEvent.originalPolicy (WebIDL attribute) §: Defined in Content Security Policy 3
SecurityPolicyViolationEventInit.originalPolicy (WebIDL dictionary member) §: Defined in Content Security Policy 3
originate (concept) §: Defined in CSS Table 3; Referenced in WebGPU Shading Language
originating element (concept) §: Defined in Selectors 4; Referenced in CSS Anchor Positioning, CSS Generated Content 3, CSS Form Control Styling 1, CSS Lists 3, CSS Multicol 2, CSS Overflow 5, CSS Positioned Layout 4, CSS Pseudo-Elements 4, CSS Shadow Parts, CSS Values 5, CSS View Transitions 1, CSS View Transitions 2, Paint Timing, Web Animations, WebVTT: The Web Video Text Tracks Format
originating pseudo-element (concept) §: Defined in Selectors 4; Referenced in CSS View Transitions 1, CSS View Transitions 2
DocumentTimelineOptions.originTime (WebIDL dictionary member) §: Defined in Web Animations
oriya (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
@ornaments (CSS @rule for @font-feature-values ) §: Defined in CSS Fonts 4; Referenced in CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
CSSFontFeatureValuesRule.ornaments (WebIDL attribute) §: Defined in CSS Fonts 4
ornaments(<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
orphans (CSS property) §: Defined in CSS Fragmentation 3 , CSS Fragmentation 4 , CSS 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Cascading 3, CSS Cascading 4, CSS Cascading 5, CSS Inline Layout 3, CSS Multicol 1, CSS Multicol 2, CSS Overflow 4, CSS Paged Media 3, CSS Text 4, CSS Typed OM 1, CSS Values 3, CSS Values 4
OscillatorNode (WebIDL interface) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefineddetune, undefinedfrequency, undefinedtype, undefinedOscillatorNode(context, options), undefinedsetPeriodicWave(periodicWave); see also WebIDLPedia
new OscillatorNode(context, options) (WebIDL constructor) §
new OscillatorNode(context, options) (WebIDL constructor) §: Defined in Web Audio API , Web Audio API 1.1
OscillatorOptions (WebIDL dictionary) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: undefineddetune, undefinedfrequency, undefinedperiodicWave, undefinedtype; see also WebIDLPedia
OscillatorType (WebIDL enumeration) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: value custom, value sawtooth, value sine, value square, value triangle; see also WebIDLPedia
NavigatorID.oscpu (WebIDL attribute) §: Defined in HTML
JsonWebKey.oth (WebIDL dictionary member) §: Defined in Web Cryptography 2
"other" (value for ScriptWindowAttribution WebIDL enumeration) §: Defined in Long Animation Frames API
"other" (value for ConnectionType WebIDL enumeration) §: Defined in Network Information API
"other" (value for USBRecipient WebIDL enumeration) §: Defined in WebUSB API
"other" (value for MediaSessionEnterPictureInPictureReason WebIDL enumeration) §: Defined in Media Session
"other" (value for RTCQualityLimitationReason WebIDL enumeration) §: Defined in WebRTC Statistics
other applicable specifications (concept) §: Defined in DOM
Othographic syllable (concept) §: Defined in Internationalization Glossary
CredentialRequestOptions.otp (WebIDL dictionary member) §: Defined in WebOTP API
otp-credentials-feature (concept) §: Defined in WebOTP API; Referenced in Credential Management 1
otpcredential (concept) §: Defined in HTML
OTPCredential (WebIDL interface) §: Defined in WebOTP API; Referenced in HTML; Related terms: OTPCredential.code, OTPCredential.[[type]], OTPCredential.[[DiscoverFromExternalSource]](origin, options, sameOriginWithAncestors); see also WebIDLPedia
OTPCredentialRequestOptions (WebIDL dictionary) §: Defined in WebOTP API; Related terms: OTPCredentialRequestOptions.transport; see also WebIDLPedia
OTPCredentialTransportType (WebIDL enumeration) §: Defined in WebOTP API; Related terms: value sms; see also WebIDLPedia
"out" (value for USBDirection WebIDL enumeration) §: Defined in WebUSB API
out (value for operator attribute of feComposite ) §: Defined in Filter Effects 1
out of flow (concept) §: Defined in CSS Display 3 , CSS Display 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Box Alignment 3, CSS Fragmentation 3, CSS Flexbox 1, CSS Inline Layout 3, CSS Multicol 1, CSS Multicol 2, CSS Overflow 3, CSS Overflow 4, CSS Page Floats, CSS Positioned Layout 3, CSS Pseudo-Elements 4, CSS Table 3, CSS Text 3, CSS Text 4, CSS Text Decoration 3, CSS Text Decoration 4
out of gamut (concept) §: Defined in CSS Color 4 , CSS Color 5
out-of-band outline (concept) §: Defined in CSS Positioned Layout 4
"out-of-memory" (value for GPUErrorFilter WebIDL enumeration) §: Defined in WebGPU
:out-of-range (CSS selector) §: Defined in Selectors 4
"outbound-rtp" (value for RTCStatsType WebIDL enumeration) §: Defined in WebRTC Statistics
outer box-shadow (concept for box-shadow ) §: Defined in CSS Backgrounds 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Borders and Box Decorations 4, CSS Overflow 3, CSS Overflow 4
outer box-shadow (CSS value for box-shadow-position ) §: Defined in CSS Borders and Box Decorations 4
outer display type (concept) §: Defined in CSS Display 3 , CSS Display 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Lists 3, CSS Ruby Annotation Layout 1, CSS Table 3
outer edge (concept) §: Defined in CSS Box Model 3 , CSS Box Model 4; Referenced in CSS Paged Media 3, CSS Positioned Layout 3
outer size (concept) §: Defined in CSS Sizing 3; Referenced in CSS Flexbox 1, CSS Grid Layout 3, CSS Inline Layout 3, CSS Multicol 2, CSS Sizing 4
outerHeight (WebIDL attribute for Window ) §: Defined in CSSOM View
Element.outerHTML (WebIDL attribute) §: Defined in HTML; Referenced in Trusted Types
outermost svg element (concept) §: Defined in SVG 2; Referenced in SVG Animations 2
HTMLElement.outerText (WebIDL attribute) §: Defined in HTML
outerWidth (WebIDL attribute for Window ) §: Defined in CSSOM View
WebTransportDatagramDuplexStream.[[OutgoingDatagramsExpirationDuration]] (internal slot) §: Defined in WebTransport
WebTransportDatagramDuplexStream.[[OutgoingDatagramsHighWaterMark]] (internal slot) §: Defined in WebTransport
WebTransportDatagramsWritable.[[OutgoingDatagramsQueue]] (internal slot) §: Defined in WebTransport
WebTransportDatagramDuplexStream.outgoingHighWaterMark (WebIDL attribute) §: Defined in WebTransport
WebTransportDatagramDuplexStream.outgoingMaxAge (WebIDL attribute) §: Defined in WebTransport
WebTransportDatagramDuplexStream.[[OutgoingMaxDatagramSize]] (internal slot) §: Defined in WebTransport
outline (CSS property) §: Defined in CSS User Interface 3 , CSS User Interface 4 , CSS 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Inline Layout 3, CSS Positioned Layout 4, CSS Pseudo-Elements 4, CSS Typed OM 1, Filter Effects 1, WebVTT: The Web Video Text Tracks Format
outline-color (CSS property) §: 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, CSS Color Adjustment 1, CSS Typed OM 1, CSS Values 3, CSS Values 4, CSSOM; Related terms: CSS value auto, CSS value invert
<outline-line-style> (CSS type) §: Defined in CSS User Interface 4
outline-offset (CSS property) §: Defined in CSS User Interface 3 , CSS User Interface 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Borders and Box Decorations 4, CSS Typed OM 1
outline-style (CSS property) §: 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, CSS Typed OM 1
outline-width (CSS property) §: 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, CSS Borders and Box Decorations 4, CSS Typed OM 1
output (markup element) §: Defined in HTML; Referenced in Web Platform Design Principles, HTML Accessibility API Mappings 1.0, ARIA in HTML, WAI-ARIA, WAI-ARIA, WebDriver; Related terms: concept form owner, markup attribute autocomplete, markup attribute disabled, markup attribute for, markup attribute form, markup attribute name
"output" (value for MIDIPortType WebIDL enumeration) §: Defined in Web MIDI API
AudioDecoderInit.output (WebIDL dictionary member) §: Defined in WebCodecs
AudioEncoderInit.output (WebIDL dictionary member) §: Defined in WebCodecs
MLBatchNormalizationSupportLimits.output (WebIDL dictionary member) §: Defined in Web Neural Network API
MLBinarySupportLimits.output (WebIDL dictionary member) §: Defined in Web Neural Network API
MLConcatSupportLimits.output (WebIDL dictionary member) §: Defined in Web Neural Network API
MLConv2dSupportLimits.output (WebIDL dictionary member) §: Defined in Web Neural Network API
MLGatherSupportLimits.output (WebIDL dictionary member) §: Defined in Web Neural Network API
MLGemmSupportLimits.output (WebIDL dictionary member) §: Defined in Web Neural Network API
MLGruCellSupportLimits.output (WebIDL dictionary member) §: Defined in Web Neural Network API
MLLogicalNotSupportLimits.output (WebIDL dictionary member) §: Defined in Web Neural Network API
MLNormalizationSupportLimits.output (WebIDL dictionary member) §: Defined in Web Neural Network API
MLOpSupportLimits.output (WebIDL dictionary member) §: Defined in Web Neural Network API
MLPreluSupportLimits.output (WebIDL dictionary member) §: Defined in Web Neural Network API
MLQuantizeDequantizeLinearSupportLimits.output (WebIDL dictionary member) §: Defined in Web Neural Network API
MLScatterSupportLimits.output (WebIDL dictionary member) §: Defined in Web Neural Network API
MLSingleInputSupportLimits.output (WebIDL dictionary member) §: Defined in Web Neural Network API
MLWhereSupportLimits.output (WebIDL dictionary member) §: Defined in Web Neural Network API
VideoDecoderInit.output (WebIDL dictionary member) §: Defined in WebCodecs
VideoEncoderInit.output (WebIDL dictionary member) §: Defined in WebCodecs
AudioDecoder.[[output callback]] (internal slot) §: Defined in WebCodecs
AudioEncoder.[[output callback]] (internal slot) §: Defined in WebCodecs
VideoDecoder.[[output callback]] (internal slot) §: Defined in WebCodecs
VideoEncoder.[[output callback]] (internal slot) §: Defined in WebCodecs; Referenced in H.264, H.265
output of the cascade (concept) §: Defined in CSS Cascading 3 , CSS Cascading 4 , CSS Cascading 5 , CSS Cascading 6; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
output progress value (concept for easing function ) §: Defined in CSS Easing Functions 2; Referenced in CSS Animations 1, CSS Transitions
"output-downscaled" (value for MediaKeyStatus WebIDL enumeration) §: Defined in Encrypted Media Extensions
"output-restricted" (value for MediaKeyStatus WebIDL enumeration) §: Defined in Encrypted Media Extensions
MLGruSupportLimits.output0 (WebIDL dictionary member) §: Defined in Web Neural Network API
MLLstmCellSupportLimits.output0 (WebIDL dictionary member) §: Defined in Web Neural Network API
MLLstmSupportLimits.output0 (WebIDL dictionary member) §: Defined in Web Neural Network API
HMACGetSecretOutput.output1 (WebIDL dictionary member) §: Defined in CTAP
MLGruSupportLimits.output1 (WebIDL dictionary member) §: Defined in Web Neural Network API
MLLstmCellSupportLimits.output1 (WebIDL dictionary member) §: Defined in Web Neural Network API
MLLstmSupportLimits.output1 (WebIDL dictionary member) §: Defined in Web Neural Network API
HMACGetSecretOutput.output2 (WebIDL dictionary member) §: Defined in CTAP
MLLstmSupportLimits.output2 (WebIDL dictionary member) §: Defined in Web Neural Network API
AudioProcessingEvent.outputBuffer (WebIDL attribute) §
AudioProcessingEvent.outputBuffer (WebIDL attribute) §: Defined in Web Audio API , Web Audio API 1.1
AudioProcessingEventInit.outputBuffer (WebIDL dictionary member) §
AudioProcessingEventInit.outputBuffer (WebIDL dictionary member) §: Defined in Web Audio API , Web Audio API 1.1
AudioWorkletNodeOptions.outputChannelCount (WebIDL dictionary member) §
AudioWorkletNodeOptions.outputChannelCount (WebIDL dictionary member) §: Defined in Web Audio API , Web Audio API 1.1
MLArgMinMaxOptions.outputDataType (WebIDL dictionary member) §: Defined in Web Neural Network API
MLGraph.[[outputDescriptors]] (internal slot) §: Defined in Web Neural Network API
Rewriter.outputLanguage (WebIDL attribute) §: Defined in Writing Assistance APIs
RewriterCreateCoreOptions.outputLanguage (WebIDL dictionary member) §: Defined in Writing Assistance APIs
Summarizer.outputLanguage (WebIDL attribute) §: Defined in Writing Assistance APIs
SummarizerCreateCoreOptions.outputLanguage (WebIDL dictionary member) §: Defined in Writing Assistance APIs
Writer.outputLanguage (WebIDL attribute) §: Defined in Writing Assistance APIs
WriterCreateCoreOptions.outputLanguage (WebIDL dictionary member) §: Defined in Writing Assistance APIs
AudioContext.outputLatency (WebIDL attribute) §
AudioContext.outputLatency (WebIDL attribute) §: Defined in Web Audio API , Web Audio API 1.1; Referenced in Playout Statistics API for WebAudio
MLConvTranspose2dOptions.outputPadding (WebIDL dictionary member) §: Defined in Web Neural Network API
HIDCollectionInfo.outputReports (WebIDL dictionary member) §: Defined in WebHID API
MIDIAccess.outputs (WebIDL attribute) §: Defined in Web MIDI API
MLSplitSupportLimits.outputs (WebIDL dictionary member) §: Defined in Web Neural Network API
MLPool2dOptions.outputShapeRounding (WebIDL dictionary member) §: Defined in Web Neural Network API
MLConvTranspose2dOptions.outputSizes (WebIDL dictionary member) §: Defined in Web Neural Network API
MLPool2dOptions.outputSizes (WebIDL dictionary member) §: Defined in Web Neural Network API
outset (CSS value for <line-style>, border property, border-bottom-style property, border-left-style property, border-right-style property, border-style property, border-top-style property ) §: 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
outset (CSS value for box-shadow-position ) §: Defined in CSS Borders and Box Decorations 4
outset (CSS value for <border-style>, border-bottom-style property, border-left-style property, border-right-style property, border-style property, border-top-style property ) §: Defined in CSS 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2025
outset (CSS value for stroke-align ) §: Defined in CSS Fill and Stroke 3
outset-adjusted border radius (concept) §: Defined in CSS Backgrounds 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Borders and Box Decorations 4, CSS Shapes 1
outside (CSS value for anchor() ) §: Defined in CSS Anchor Positioning
outside (CSS value for list-style-position ) §: Defined in CSS Lists 3 , CSS 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2025, CSS Exclusions 1
outside-shape (CSS value for shape-inside ) §: Defined in CSS Shapes 2
outstanding-network-request (concept) §: Defined in HTML
over (CSS value for ruby-position ) §: Defined in CSS Ruby Annotation Layout 1
over (CSS value for text-emphasis-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
over (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 Inline Layout 3, CSS Rhythmic Sizing, CSS Text Decoration 4
over (value for operator attribute of feComposite ) §: Defined in Filter Effects 1
overallProgress (concept for animation ) §: Defined in Web Animations 2
Animation.overallProgress (WebIDL attribute) §: Defined in Web Animations 2
OverconstrainedError (WebIDL interface) §: Defined in Media Capture and Streams; Referenced in MediaStreamTrack Insertable Media Processing using Streams; Related terms: OverconstrainedError.constraint, WebIDL constructor constructor(); see also WebIDLPedia
overflow (concept) §: Defined in CSS Overflow 3; Referenced in CSS Borders and Box Decorations 4, CSS Display 3, CSS Display 4, CSS Overscroll Behavior 1
overflow (CSS property) §: Defined in CSS Overflow 3 , CSS 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2025, CSS Box Alignment 3, CSS Anchor Positioning, CSS Backgrounds 3, CSS Borders and Box Decorations 4, CSS Fragmentation 3, CSS Fragmentation 4, CSS Containment 1, CSS Containment 2, CSS Display 3, CSS Display 4, CSS Flexbox 1, CSS Layout API 1, CSS Lists 3, CSS Masking 1, CSS Multicol 1, CSS Multicol 2, CSS Overflow 4, CSS Overflow 5, CSS Positioned Layout 4, CSS Regions 1, CSS Scroll Snap 1, CSS Scrollbars Styling 1, CSS Sizing 4, CSS Table 3, CSS Transforms 1, CSS Transforms 2, CSS Typed OM 1, CSS User Interface 4, CSS Values 3, CSS Values 4, CSS View Transitions 1, CSS View Transitions 2, CSSOM, CSSOM View, Filter Effects 1, WebVTT: The Web Video Text Tracks Format
overflow (CSS value for continue ) §: Defined in CSS Overflow 5
overflow alignment (concept) §: Defined in CSS Box Alignment 3; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Positioned Layout 3
overflow clip edge (concept) §: Defined in CSS Overflow 3 , CSS Overflow 4; Referenced in CSS Anchor Positioning, CSS Borders and Box Decorations 4, CSS Containment 1, CSS Containment 2
overflow columns (concept) §: Defined in CSS Multicol 1 , CSS Multicol 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Overflow 4, CSS Overflow 5
overflow-anchor (CSS property) §: Defined in CSS Scroll Anchoring 1; Referenced in CSS Scroll Snap 1, CSS Typed OM 1; Related terms: CSS value auto, CSS value none
overflow-block (CSS property) §: Defined in CSS Overflow 3; Related terms: CSS value overlay
overflow-block (CSS descriptor for @media ) §: Defined in Media Queries 4 , Media Queries 5; Related terms: CSS value none, CSS value paged, CSS value scroll
overflow-clip-margin (CSS property) §: Defined in CSS Overflow 3 , CSS Overflow 4; Referenced in CSS Backgrounds 3, CSS Borders and Box Decorations 4, CSS Containment 1, CSS Containment 2
overflow-clip-margin-block (CSS property) §: Defined in CSS Overflow 4
overflow-clip-margin-block-end (CSS property) §: Defined in CSS Overflow 4
overflow-clip-margin-block-start (CSS property) §: Defined in CSS Overflow 4
overflow-clip-margin-bottom (CSS property) §: Defined in CSS Overflow 4
overflow-clip-margin-inline (CSS property) §: Defined in CSS Overflow 4
overflow-clip-margin-inline-end (CSS property) §: Defined in CSS Overflow 4
overflow-clip-margin-inline-start (CSS property) §: Defined in CSS Overflow 4
overflow-clip-margin-left (CSS property) §: Defined in CSS Overflow 4
overflow-clip-margin-right (CSS property) §: Defined in CSS Overflow 4
overflow-clip-margin-top (CSS property) §: Defined in CSS Overflow 4
overflow-inline (CSS property) §: Defined in CSS Overflow 3; Related terms: CSS value overlay
overflow-inline (CSS descriptor for @media ) §: Defined in Media Queries 4 , Media Queries 5; Related terms: CSS value none, CSS value scroll
<overflow-position> (CSS type) §: Defined in CSS Box Alignment 3; Referenced in CSS Typed OM 1; Related terms: CSS value safe, CSS value unsafe
overflow-wrap (CSS property) §: Defined in CSS Text 3 , CSS Text 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025, CSS Overflow 4, WebVTT: The Web Video Text Tracks Format; Related terms: CSS value anywhere, CSS value break-word, CSS value normal
overflow-x (CSS property) §: Defined in CSS Overflow 3; Referenced in CSS Containment 1, CSS Containment 2, CSS Spatial Navigation 1, CSS Overflow 4, CSS Typed OM 1, CSSOM View; Related terms: CSS value auto, CSS value clip, CSS value hidden, CSS value overlay, CSS value scroll, CSS value visible
overflow-y (CSS property) §: Defined in CSS Overflow 3; Referenced in CSS Containment 1, CSS Containment 2, CSS Spatial Navigation 1, CSS Overflow 4, CSS Typed OM 1, CSSOM View; Related terms: CSS value auto, CSS value clip, CSS value hidden, CSS value overlay, CSS value scroll, CSS value visible
overlay (CSS value for <blend-mode> ) §: Defined in Compositing 2 , Compositing 1; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
overlay (CSS value for overflow, overflow-block property, overflow-inline property, overflow-x property, overflow-y property ) §: Defined in CSS Overflow 3
overlay (CSS property) §: Defined in CSS Positioned Layout 4; Referenced in Filter Effects 1; Related terms: CSS value auto, CSS value none
overlay scrollbars (concept) §: Defined in CSS Overflow 3; Referenced in CSS Overflow 4, CSS Scrollbars Styling 1
VirtualKeyboard.overlaysContent (WebIDL attribute) §: Defined in VirtualKeyboard API
overline (CSS value for text-decoration-line ) §: Defined in CSS Text Decoration 3 , CSS Text Decoration 4; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2024, CSS Snapshot 2025
overline (CSS value for text-decoration ) §: Defined in CSS 2; Referenced in CSS Snapshot 2022, CSS Snapshot 2023, CSS Snapshot 2025
overload resolution algorithm (concept) §: Defined in Web IDL; Referenced in HTML
overloaded (concept) §: Defined in Web IDL; Referenced in Isolated Contexts
overridden constructor steps (concept) §: Defined in Web IDL; Referenced in HTML
PreferenceObject.override (WebIDL attribute) §: Defined in Media Queries 5
override-colors (CSS descriptor for @font-palette-values ) §: Defined in CSS Fonts 4
CSSFontPaletteValuesRule.overrideColors (WebIDL attribute) §: Defined in CSS Fonts 4
XMLHttpRequest.overrideMimeType(mime) (WebIDL operation) §: Defined in XMLHttpRequest
WaveShaperNode.oversample (WebIDL attribute) §
WaveShaperNode.oversample (WebIDL attribute) §: Defined in Web Audio API , Web Audio API 1.1
WaveShaperOptions.oversample (WebIDL dictionary member) §
WaveShaperOptions.oversample (WebIDL dictionary member) §: Defined in Web Audio API , Web Audio API 1.1
OverSampleType (WebIDL enumeration) §: Defined in Web Audio API , Web Audio API 1.1; Related terms: value 2x, value 4x, value none; see also WebIDLPedia
overscroll-behavior (CSS property) §: Defined in CSS Overscroll Behavior 1; Related terms: CSS value auto, CSS value contain, CSS value none
overscroll-behavior-block (CSS property) §: Defined in CSS Overscroll Behavior 1; Related terms: CSS value auto, CSS value contain, CSS value none
overscroll-behavior-inline (CSS property) §: Defined in CSS Overscroll Behavior 1; Related terms: CSS value auto, CSS value contain, CSS value none
overscroll-behavior-x (CSS property) §: Defined in CSS Overscroll Behavior 1; Related terms: CSS value auto, CSS value contain, CSS value none
overscroll-behavior-y (CSS property) §: Defined in CSS Overscroll Behavior 1; Related terms: CSS value auto, CSS value contain, CSS value none
OverscrollEvent (WebIDL interface for OverscrollEvent ) §: Defined in overscroll and scrollend events; Related terms: OverscrollEvent.deltaX, OverscrollEvent.deltaY, WebIDL interface OverscrollEvent; see also WebIDLPedia
OverscrollEventInit (WebIDL dictionary for OverscrollEventInit ) §: Defined in overscroll and scrollend events; Related terms: OverscrollEventInit.deltaX, OverscrollEventInit.deltaY, WebIDL dictionary OverscrollEventInit; see also WebIDLPedia
NamedFlow.overset (WebIDL attribute) §: Defined in CSS Regions 1
NDEFWriteOptions.overwrite (WebIDL dictionary member) §: Defined in Web NFC
owner (concept for interest group descriptor ) §: Defined in Fenced Frame; Referenced in Protected Audience
AuctionAdInterestGroupKey.owner (WebIDL dictionary member) §: Defined in Protected Audience
GenerateBidInterestGroup.owner (WebIDL dictionary member) §: Defined in Protected Audience
owner node (concept for CSSStyleDeclaration ) §: Defined in CSSOM; Referenced in CSS Anchor Positioning, CSS Animations 1, CSS Cascading 6, CSS Functions and Mixins, CSS Nesting, Referrer Policy, Web Animations
owner set (concept for WorkerGlobalScope ) §: Defined in HTML; Referenced in Scripting Policy, Document-Isolation-Policy, Prerendering Revamped, Page Lifecycle, Compute Pressure 1, Mitigating Browser Fingerprinting in Web Specifications, Service Workers, WebCodecs, WebDriver BiDi
Node.ownerDocument (WebIDL attribute) §: Defined in DOM; Referenced in execCommand, HTMLVideoElement.requestVideoFrameCallback(), WebCodecs, WebVTT: The Web Video Text Tracks Format
Attr.ownerElement (WebIDL attribute) §: Defined in DOM
StyleSheet.ownerNode (WebIDL attribute) §: Defined in CSSOM
CSSStyleSheet.ownerRule (WebIDL attribute) §: Defined in CSSOM
SVGElement.ownerSVGElement (WebIDL attribute) §: Defined in SVG 2
owning document (concept for DedicatedWorkerGlobalScope ) §: Defined in Page Lifecycle
Reflect.ownKeys(target) (WebIDL operation) §: Defined in ECMAScript