RTCDataChannel: message 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.
The WebRTCmessage
event is sent to theonmessage
event handler on anRTCDataChannel
object when a message has been received from the remote peer.
Note:Themessage
event uses as its event object type theMessageEvent
interface defined by the HTML specification.
This event is not cancelable and does not bubble.
Syntax
Use the event name in methods likeaddEventListener()
, or set an event handler property.
addEventListener("message", (event) => { })onmessage = (event) => { }
Event type
AMessageEvent
. Inherits fromEvent
.
Event properties
Also inherits properties from its parent interface,Event
.
MessageEvent.data
Read onlyThe data sent by the message emitter.
MessageEvent.origin
Read onlyA string representing the origin of the message emitter.
MessageEvent.lastEventId
Read onlyA string representing a unique ID for the event.
MessageEvent.source
Read onlyA reference to the message emitter, one ofWindowProxy,
MessagePort
, orServiceWorker
.MessageEvent.ports
Read onlyAn array of
MessagePort
objects representing the ports associated with the channel the message is being sent through (where appropriate, e.g., in channel messaging or when sending a message to a shared worker).
Examples
For a givenRTCDataChannel
,dc
, created for a peer connection using itscreateDataChannel()
method, this code sets up a handler for incoming messages and acts on them by adding the data contained within the message to the current document as a new<p>
(paragraph) element.
dc.addEventListener( "message", (event) => { let newParagraph = document.createElement("p"); let textNode = document.createTextNode(event.data); newParagraph.appendChild(textNode); document.body.appendChild(newParagraph); }, false,);
We first create the new paragraph element and add the message data to it as a new text node. Then we append the new paragraph to the end of the document's body.
You can also use anRTCDataChannel
object'sonmessage
event handler property to set the event handler:
dc.onmessage = (event) => { let newParagraph = document.createElement("p"); let textNode = document.createTextNode(event.data); newParagraph.appendChild(textNode); document.body.appendChild(newParagraph);};
Specifications
Specification |
---|
WebRTC: Real-Time Communication in Browsers # event-datachannel-message |
WebRTC: Real-Time Communication in Browsers # dom-rtcdatachannel-onmessage |
Browser compatibility
See also
- WebRTC API
- A simple RTCDataChannel example
- Related events:
open
,close
, anderror
RTCDataChannel.send()