RTCPeerConnection.onicecandidate

The RTCPeerConnection property onicecandidate property is an EventHandler which specifies a function to be called when the icecandidate event occurs on an RTCPeerConnection instance. This happens whenever the local ICE agent needs to deliver a message to the other peer through the signaling server. This lets the ICE agent perform negotiation with the remote peer without the browser itself needing to know any specifics about the technology being used for signaling; simply implement this method to use whatever messaging technology you choose to send the ICE candidate to the remote peer.

Syntax

rtcPeerConnection.onicecandidate = eventHandler;

Value

This should be set to a function which you provide that accepts as input an RTCPeerConnectionIceEvent object representing the icecandidate event. The function should deliver the ICE candidate, whose SDP can be found in the event's candidate property, to the remote peer through the signaling server.

If the event's candidate property is null, ICE gathering has finished. This message should not be sent to the remote peer. When this happens, the connection's iceGatheringState has also changed to complete. You don't need to watch for this explicitly; instead, if you need to sense the end of signaling, you should watch for a icegatheringstatechange event indicating that the ICE negotiation has transitioned to the complete state.

Example

The example below, which is based on the code from the article Signaling and video calling, sets up a handler for icecandidate events to send the candidates to the remote peer.

pc.onicecandidate = function(event) {
  if (event.candidate) {
    // Send the candidate to the remote peer
  } else {
    // All ICE candidates have been sent
  }
}

Notice that the end of negotiation is detected here when the event's candidate property is null.

Specifications

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

Browser compatibility

DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
onicecandidateChrome Full support 24Edge Full support 15Firefox Full support 22IE No support NoOpera Full support 43
Notes
Full support 43
Notes
Notes Promise-based version.
No support 37 — 43
Safari Full support 11WebView Android Full support YesChrome Android Full support YesFirefox Android Full support 44Opera Android Full support 43
Notes
Full support 43
Notes
Notes Promise-based version.
No support 37 — 43
Safari iOS Full support YesSamsung Internet Android Full support 6.0

Legend

Full support
Full support
No support
No support
See implementation notes.
See implementation notes.

See also