AudioTrackList: length property
Limited availability
This feature is not Baseline because it does not work in some of the most widely-used browsers.
The read-only AudioTrackList
property length returns the number of entries in the
AudioTrackList, each of which is an AudioTrack
representing one audio track in the media element. A value of 0 indicates that
there are no audio tracks in the media.
Value
A number indicating how many audio tracks are included in the
AudioTrackList. Each track can be accessed by treating the
AudioTrackList as an array of objects of type AudioTrack.
Examples
This snippet gets the number of audio tracks in the first <video>
element found in the DOM by querySelector().
const videoElem = document.querySelector("video");
let numAudioTracks = 0;
if (videoElem.audioTracks) {
numAudioTracks = videoElem.audioTracks.length;
}
Note that this sample checks to be sure HTMLMediaElement.audioTracks is
defined, to avoid failing on browsers without support for AudioTrack.
Specifications
| Specification |
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| HTML # dom-audiotracklist-length-dev |
Browser compatibility
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Legend
Tip: you can click/tap on a cell for more information.
- Full support
- Full support
- No support
- No support
- User must explicitly enable this feature.
- Has more compatibility info.