The WebRTC open event is sent to an RTCDataChannel object's onopen 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.

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

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

onopen = (event) => {};

An RTCDataChannelEvent. Inherits from Event.

Also inherits properties from its parent interface, Event.

channel Read only

Returns the RTCDataChannel associated with the event.

This example adds to the RTCDataChannel dc a handler for the open 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();
  },
  false,
);

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

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

  messageInputBox.focus();
};

• WebRTC API
• A simple RTCDataChannel example
• Related events: message, close, and error