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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

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
connectionstatechange_event 72 79 113 No 60 11 72 72 113 51 11 11.0

See also

© 2005–2023 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/RTCPeerConnection/connectionstatechange_event