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
Specification | Status | Comment |
---|---|---|
HTML Living Standard The definition of 'VideoTrackList: length' in that specification. |
Living Standard |
Browser compatibility
The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
length | Chrome
Full support
45
| Edge
Full support
79
| Firefox
Full support
33
| IE Full support 10 | Opera
Full support
32
| Safari Full support 6.1 | WebView Android Full support 45 | Chrome Android
Full support
45
| Firefox Android
Full support
33
| Opera Android
Full support
32
| Safari iOS Full support 7 | Samsung Internet Android No support No |
Legend
- Full support
- Full support
- No support
- No support
- User must explicitly enable this feature.
- User must explicitly enable this feature.