VideoTrackList: addtrack event
        
        
          Limited availability
        
        
        
          
                
              
                
              
                
              
        
        
      
      This feature is not Baseline because it does not work in some of the most widely-used browsers.
The addtrack event is fired when a video track is added to a VideoTrackList.
Syntax
Use the event name in methods like addEventListener(), or set an event handler property.
js
addEventListener("addtrack", (event) => { })
onaddtrack = (event) => { }
Event type
A TrackEvent. Inherits from Event.
Event properties
In addition to the properties listed below, properties from the parent interface, Event, are available.
trackRead only- 
The newly-added
VideoTrackthe event is in reference to. 
Examples
Using addEventListener():
js
const videoElement = document.querySelector("video");
videoElement.videoTracks.addEventListener("addtrack", (event) => {
  console.log(`Video track: ${event.track.label} added`);
});
Using the onaddtrack event handler property:
js
const videoElement = document.querySelector("video");
videoElement.videoTracks.onaddtrack = (event) => {
  console.log(`Video track: ${event.track.label} added`);
};
Specifications
| Specification | 
|---|
| HTML> # event-media-addtrack>  | 
            
| HTML> # handler-tracklist-onaddtrack>  | 
            
Browser compatibility
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See also
- Related events: 
removetrack,change - This event on 
AudioTrackListtargets:addtrack - This event on 
MediaStreamtargets:addtrack - Media Capture and Streams API
 - WebRTC