The RTCIceTransport interface's onselectedcandidatepairchange event handler specifies a function to be called to handle the selectedcandidatepairchange event, which is fired when the ICE agent selects a new candidate pair to be used for the connection.


RTCIceTransport.onselectedcandidatepairchange = candidatePairHandler;


This propoerty should be set to reference an event handler function to be called by the ICE agent when it discovers a new candidate pair that the RTCIceTransport will be using for communication with the remote peer. This event will occur at least once, and may occur more than once if the ICE agent continues to identify candidate pairs that will work better, more closely match the requested parameters, and so forth.

The event handler can determine the current state by calling the transport's getSelectedCandidatePair() method, which returns a RTCIceCandidatePair whose RTCIceCandidatePair.local and RTCIceCandidatePair.global properties specify RTCIceCandidate objects describing the local and remote candidates that are currently being used.


In this example, an event handler for selectedcandidatepairchange is set up to update an on-screen display showing the protocol used by the currently selected candidate pair.

var iceTransport = pc.getSenders()[0].transport.iceTransport;
var localProto = document.getElementById("local-protocol");
var remoteProto = document.getElementById("remote-protocol");

iceTransport.onselectedcandidatepairchange = function(event) {
  var pair = iceTransport.getSelectedCandidatePair();
  localProtocol.innerText = pair.local.protocol.toUpperCase();
  remoteProtocol.innerText = pair.remote.protocol.toUpperCase();


WebRTC 1.0: Real-Time Communication Between Browsers (WebRTC 1.0)
# dom-rtcicetransport-onselectedcandidatepairchange

Browser compatibility

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See also