W3cubDocs

/DOM

VideoTrackList.length

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.

Syntax

var trackCount = VideoTrackList.length;

Value

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.

Example

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.

Specifications

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
Basic support 45
Disabled
45
Disabled
Disabled From version 45: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled). To change preferences in Chrome, visit chrome://flags.
12 33
Disabled
33
Disabled
Disabled From version 33: this feature is behind the media.track.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
10 32
Disabled
32
Disabled
Disabled From version 32: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
6.1
Mobile
Android webview Chrome for Android Edge Mobile Firefox for Android Opera for Android iOS Safari Samsung Internet
Basic support 45 45
Disabled
45
Disabled
Disabled From version 45: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled). To change preferences in Chrome, visit chrome://flags.
Yes 33
Disabled
33
Disabled
Disabled From version 33: this feature is behind the media.track.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
32
Disabled
32
Disabled
Disabled From version 32: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
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