RTCPeerConnection: connectionstatechange event

The connectionstatechange event is sent to the onconnectionstatechange event handler on an RTCPeerConnection object after a new track has been added to an RTCRtpReceiver which is part of the connection. The new connection state can be found in connectionState, and is one of the string values: new, connecting, connected, disconnected, failed, or closed.

This event is not cancelable and does not bubble.

Syntax

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

js
addEventListener("connectionstatechange", (event) => {});

onconnectionstatechange = (event) => {};

Event type

A generic Event.

Examples

For an RTCPeerConnection named peerConnection, this example uses addEventListener() to handle changes to the connectivity of the WebRTC session. It calls an app-defined function called setOnlineStatus() to update a status display.

js
peerConnection.addEventListener(
  "connectionstatechange",
  (event) => {
    switch (peerConnection.connectionState) {
      case "new":
      case "connecting":
        setOnlineStatus("Connecting…");
        break;
      case "connected":
        setOnlineStatus("Online");
        break;
      case "disconnected":
        setOnlineStatus("Disconnecting…");
        break;
      case "closed":
        setOnlineStatus("Offline");
        break;
      case "failed":
        setOnlineStatus("Error");
        break;
      default:
        setOnlineStatus("Unknown");
        break;
    }
  },
  false,
);

You can also create a handler for the connectionstatechange event using the RTCPeerConnection.onconnectionstatechange property:

js
peerConnection.onconnectionstatechange = (ev) => {
  switch (peerConnection.connectionState) {
    case "new":
    case "connecting":
      setOnlineStatus("Connecting…");
      break;
    // …
    default:
      setOnlineStatus("Unknown");
      break;
  }
};

Specifications

Specification
WebRTC: Real-Time Communication in Browsers
# dom-rtcpeerconnection-onconnectionstatechange

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
connectionstatechange event

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support

See also