RTCDataChannel: open event

Baseline Widely available

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

The WebRTCopen event is sent to anRTCDataChannel object'sonopen event handler when the underlying transport used to send and receive the data channel's messages is opened or reopened.

This event is not cancelable and does not bubble.

Syntax

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

addEventListener("open", (event) => { })onopen = (event) => { }

Event type

AnRTCDataChannelEvent. Inherits fromEvent.

Event properties

Also inherits properties from its parent interface,Event.

channelRead only: Returns theRTCDataChannel associated with the event.

This example adds to theRTCDataChanneldc a handler for theopen event that adjusts the user interface to indicate that a chat window is ready to be used after a connection has been established. It enables the message input box and send button as well as enabling the disconnect button and disabling the connect button. Finally, the message input box is focused so the user can immediately begin to type.

dc.addEventListener("open", (ev) => {  messageInputBox.disabled = false;  sendMessageButton.disabled = false;  disconnectButton.disabled = false;  connectButton.disabled = true;  messageInputBox.focus();});

This can also be done by directly setting the value of the channel'sonopen event handler property.

dc.onopen = (ev) => {  messageInputBox.disabled = false;  sendMessageButton.disabled = false;  disconnectButton.disabled = false;  connectButton.disabled = true;  messageInputBox.focus();};