The onsignalingstatechange property of the RTCPeerConnection interface is an EventHandler which specifies a function to be called when the signalingstatechange event occurs on an RTCPeerConnection interface. The function receives as input the event object, of type Event; this event is sent when the value of RTCPeerConnection.signalingState changes, as the result of a call to either setLocalDescription() or setRemoteDescription().


RTCPeerConnection.onsignalingstatechange = errorHandler;


Set this to a function which you provide that receives an Event object as input; this contains the signalingstatechange event. This event object doesn't provide details about what changed, but you can examine the signalingState property to determine what the new state is.


This snippet shows a handler for signalingstatechange that looks for the "have-local-pranswer" signaling state—indicating that a remote offer has been received and a local description of type "pranswer" has been applied in response.

pc.onsignalingstatechange = function(event) {
  if (pc.signalingState === "have-local-pranswer") {
    // setLocalDescription() has been called with an answer


Specification Status Comment
WebRTC 1.0: Real-time Communication Between Browsers
The definition of 'RTCPeerConnection.onsignalingstatechange' in that specification.
Candidate Recommendation Initial specification.

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support561522 ?


37 — 43

FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support5656 Yes44


37 — 43


1. Promise based version.

See also

Document Tags and Contributors

Contributors to this page: Sheppy, fscholz, jpmedley, abbycar, Sebastianz, teoli
Last updated by: Sheppy,