RTCPeerConnection: datachannel event

BaselineWidely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since January 2020.

Adatachannel event is sent to anRTCPeerConnection instance when anRTCDataChannel has been added to the connection, as a result of the remote peer callingRTCPeerConnection.createDataChannel().

Note:This event isnot dispatched when the local end of the connection creates the channel.

This event is not cancelable and does not bubble.

Syntax

Use the event name in methods likeaddEventListener(), or set an event handler property.

addEventListener("datachannel", (event) => { })ondatachannel = (event) => { }

Event type

AnRTCDataChannelEvent. Inherits fromEvent.

Event properties

Also inherits properties fromEvent.

channelRead only: Returns theRTCDataChannel associated with the event.

This example sets up a function that handlesdatachannel events by gathering the information needed to communicate with the newly addedRTCDataChannel and by adding event handlers for the events that occur on that channel.

pc.addEventListener(  "datachannel",  (ev) => {    receiveChannel = ev.channel;    receiveChannel.onmessage = myHandleMessage;    receiveChannel.onopen = myHandleOpen;    receiveChannel.onclose = myHandleClose;  },  false,);

receiveChannel is set to the value of the event'schannel property, which specifies theRTCDataChannel object representing the data channel linking the remote peer to the local one.

This same code can also instead use theRTCPeerConnection interface'sondatachannel event handler property, like this:

pc.ondatachannel = (ev) => {  receiveChannel = ev.channel;  receiveChannel.onmessage = myHandleMessage;  receiveChannel.onopen = myHandleOpen;  receiveChannel.onclose = myHandleClose;};