The read-only TextTrackList
property length
returns the number of entries in the TextTrackList
, each of which is a TextTrack
representing one track in the media element. A value of 0 indicates that there are no text tracks in the media.
Syntax
var trackCount = TextTrackList.length;
Value
A number indicating how many text tracks are included in the TextTrackList
. Each track can be accessed by treating the TextTrackList
as an array of objects of type TextTrack
.
Example
This snippet gets the number of text tracks in the first media element found in the DOM by querySelector()
.
var mediaElem = document.querySelector("video, audio"); var numTextTracks = 0; if (mediaElem.textTracks) { numTextTracks = mediaElem.textTracks.length; }
Note that this sample checks to be sure HTMLMediaElement.textTracks
is defined, to avoid failing on browsers without support for TextTrack
.
Specifications
Specification | Status | Comment |
---|---|---|
HTML Living Standard The definition of 'TextTrackList: 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 44 | Edge Full support ≤18 | Firefox Full support Yes | IE ? | Opera Full support 31 | Safari Full support 10 | WebView Android Full support 44 | Chrome Android Full support 44 | Firefox Android ? | Opera Android Full support 32 | Safari iOS ? | Samsung Internet Android Full support 4.0 |
Legend
- Full support
- Full support
- Compatibility unknown
- Compatibility unknown