The MediaStream.getTrackById() method returns a MediaStreamTrack object representing the track with the specified ID string. If there is no track with the specified ID, this method returns null.


var track = MediaStream.getTrackById(id);


A DOMString which identifies the track to be returned.

Return value

If a track is found for which matches the specified id string, that MediaStreamTrack object is returned. Otherwise, the returned value is null.


This example activates a commentary track on a video by ducking the audio level of the main audio track to 50%, then enabling the commentary track.

stream.getTrackById("primary-audio-track").applyConstraints({ volume: 0.5 });
stream.getTrackById("commentary-track").enabled = true;


Specification Status Comment
Media Capture and Streams
The definition of 'getTrackById()' in that specification.
Candidate Recommendation Initial specification.

Browser compatibility

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support ? 49 (49) No support ? ?
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support ? ? 49.0 (49) No support ? ?

See also

Document Tags and Contributors

 Contributors to this page: Sheppy
 Last updated by: Sheppy,