RTCPeerConnection: signalingstatechange event

Baseline

Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2017.

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A signalingstatechange event is sent to an RTCPeerConnection to notify it that its signaling state, as indicated by the signalingState property, has changed.

This event is not cancelable and does not bubble.

Syntax

Use the event name in addEventListener():

addEventListener("signalingstatechange", (event) => { })

Alternatively, assign to the event handler property of the interface:

onsignalingstatechange = (event) => { }

Given an RTCPeerConnection, pc, and an updateStatus() function that presents status information to the user, this code sets up an event handler to let the user know when the ICE negotiation process finishes up.

pc.addEventListener("signalingstatechange", (ev) => {
  switch (pc.signalingState) {
    case "stable":
      updateStatus("ICE negotiation complete");
      break;
  }
});

Using onsignalingstatechange, it looks like this (but note that this replaces other event listeners added using onsignalingstatechange, if any):

pc.onsignalingstatechange = (ev) => {
  switch (pc.signalingState) {
    case "stable":
      updateStatus("ICE negotiation complete");
      break;
  }
};