Definition
CSS Font Loading Module Level 3 defines FontFaceSet
[Exposed=(Window,Worker)]
interface FontFaceSet : EventTarget {
constructor(sequence<FontFace> initialFaces);
setlike<FontFace>;
FontFaceSet add(FontFace font);
boolean delete(FontFace font);
undefined clear();
// events for when loading state changes
attribute EventHandler onloading;
attribute EventHandler onloadingdone;
attribute EventHandler onloadingerror;
// check and start loads if appropriate
// and fulfill promise when all loads complete
Promise<sequence<FontFace>> load(CSSOMString font, optional CSSOMString text = " ");
// return whether all fonts in the fontlist are loaded
// (does not initiate load if not available)
boolean check(CSSOMString font, optional CSSOMString text = " ");
// async notification that font loading and layout operations are done
readonly attribute Promise<FontFaceSet> ready;
// loading state, "loading" while one or more fonts loading, "loaded" otherwise
readonly attribute FontFaceSetLoadStatus status;
};