AudioTrackList.onaddtrack

The AudioTrackList property onaddtrack is an event handler which is called when the addtrack event occurs, indicating that a new audio track has been added to the media element whose audio tracks the AudioTrackList represents.

The event is passed into the event handler in the form of a TrackEvent object, whose track property identifies the newly-added track.

Syntax

AudioTrackList.onaddtrack = eventHandler;

Value

Set onaddtrack to a function that accepts as input a TrackEvent object which indicates in its track property which audio track has been added to the media.

Usage notes

The addtrack event is called whenever a new track is added to the media element whose audio tracks are represented by the AudioTrackList object. This happens when tracks are added to the element when the media is first attached to the element; one addtrack event will occur for each audio track in the media resource.

Example

This snippet establishes a handler for the addtrack event that calls a function, addToTrackList(), passing in the AudioTrack object representing the newly-added track. In this scenario, that function's role is to add the new track to a list of audio tracks available to choose from.

document.querySelector("video").audioTracks.onaddtrack = function(event) {
  addToTrackList(event.track);
};

Specifications

Browser compatibility