The read-only VideoTrackList
property length
returns the number of entries in the VideoTrackList
, each of which is a VideoTrack
representing one video track in the media element. A value of 0 indicates that there are no video tracks in the media.
var trackCount = VideoTrackList.length;
A number indicating how many video tracks are included in the VideoTrackList
. Each track can be accessed by treating the VideoTrackList
as an array of objects of type VideoTrack
.
This snippet gets the number of video tracks in the first <video>
element found in the DOM by querySelector()
.
var videoElem = document.querySelector("video"); var numVideoTracks = 0; if (videoElem.videoTracks) { numVideoTracks = videoElem.videoTracks.length; }
Note that this sample checks to be sure HTMLMediaElement.videoTracks
is defined, to avoid failing on browsers without support for VideoTrack
.
Specification | Status | Comment |
---|---|---|
HTML Living Standard The definition of 'VideoTrackList: length' in that specification. | Living Standard |
Desktop | ||||||
---|---|---|---|---|---|---|
Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | |
Basic support | 45
|
12 | 33
|
10 | 32
|
6.1 |
Mobile | |||||||
---|---|---|---|---|---|---|---|
Android webview | Chrome for Android | Edge Mobile | Firefox for Android | Opera for Android | iOS Safari | Samsung Internet | |
Basic support | 45 | 45
|
Yes | 33
|
32
|
7.1 | ? |
© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/VideoTrackList/length