index.html

<video id="localVideo" autoplay></video>
<video id="remoteVideo" autoplay></video>
<br>
<input type="text" id="server" value="ws://localhost:8765">
<input type="text" id="turn" value="stun:stun.l.google.com:19302">
<input id="connect" disabled type="button" value="connect">
<script>
	//polyfills
	var RTCPeerConnection = window.RTCPeerConnection || window.webkitRTCPeerConnection || window.mozRTCPeerConnection;
	var RTCSessionDescription = window.RTCSessionDescription || window.webkitRTCSessionDescription || window.mozRTCSessionDescription;
	var RTCIceCandidate = window.RTCIceCandidate || window.webkitRTCIceCandidate || window.mozRTCIceCandidate;
	navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia;
	
	//request & load user's stream into videoA
	navigator.getUserMedia({video: true}, function(stream) {
		localVideo.src = URL.createObjectURL(stream);
		server.disabled = false; //because https://bugzilla.mozilla.org/show_bug.cgi?id=685657
		connect.disabled = false;
		connect.onclick = function() {
			connect.disabled = true;
			server.disabled = true;
			var socket = new WebSocket(server.value);
			socket.onmessage = function(event) {
				var message = JSON.parse(event.data);
				switch (message.type) {
					case 'SDP_Stage_1':
						peerConnection.createOffer(function(offerDescription) {
							peerConnection.setLocalDescription(offerDescription, function() {								
								socket.send(JSON.stringify({
									type: 'offer',
									data: offerDescription
								}));
							}, errorHandler);
						}, errorHandler);
						break;
					case 'SDP_Stage_2':
						peerConnection.setRemoteDescription(new RTCSessionDescription(message.data), function() {
							peerConnection.createAnswer(function(answerDescription) {
								peerConnection.setLocalDescription(answerDescription, function() {								
									socket.send(JSON.stringify({
										type: 'answer',
										data: answerDescription
									}));
								}, errorHandler);
							}, errorHandler);
						}, errorHandler);
						break;
					case 'SDP_Stage_3':
						peerConnection.setRemoteDescription(new RTCSessionDescription(message.data), successHandler, errorHandler);
						break;
					case 'ice':
						peerConnection.addIceCandidate(new RTCIceCandidate(message.data), successHandler, errorHandler);
						break;
				}
			}
			
			var peerConnection = new RTCPeerConnection({
				'iceServers': [{'url': turn.value}]
			});
			peerConnection.onicecandidate = function(event) {
				if (event.candidate)
					socket.send(JSON.stringify({
						type: 'ice',
						data: event.candidate
					}));
			};
			
			peerConnection.onaddstream = function(event) {
				remoteVideo.src = URL.createObjectURL(event.stream);
			};
			
			peerConnection.addStream(stream);
		};
	}, errorHandler);
	
	function errorHandler() {
		console.log(arguments);
	}
	
	function successHandler() {
		console.log(arguments);
	}
</script>