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

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Basic supportChrome Full support YesEdge Full support 12Firefox Full support 49IE No support NoOpera ? Safari ? WebView Android Full support YesChrome Android Full support YesEdge Mobile Full support YesFirefox Android Full support 49Opera Android ? Safari iOS ? Samsung Internet Android Full support Yes


Full support  
Full support
No support  
No support
Compatibility unknown  
Compatibility unknown

See also

Document Tags and Contributors

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