title: WebRTC DataChannel Errors
body: <p>I'm trying to connect 2 peers with webrtc and datachannel without camera and microphone.</p>
  
  <pre><code>try {
              socket = new WebSocket("ws://localhost:1337/");
              var servers = {iceServers:[{url:"stun:stun.l.google.com:19302"}]};
              peerConn = new webkitRTCPeerConnection(servers, {optional:[{RtpDataChannels: true}]});
              channel = peerConn.createDataChannel("abcd1234", {reliable: false});
  
              peerConn.onicecandidate = function(evt) {
                  if(evt.candidate) {
                      socket.send(JSON.stringify({"candidate": evt.candidate}));
                  }
              };
  
              channel.onopen = function () {
                  console.log("channel is open");
                  channel.send('first text message over RTP data ports');
              };
  
              channel.onmessage = function (event) {
                  console.log('received a message:', event.data);
              };
  
              peerConn.createOffer(function(desc) {
                  peerConn.setLocalDescription(desc);
                  socket.send(JSON.stringify({"sdp": desc}));
              });
  
              socket.onmessage = function(evt) {
                  var signal = JSON.parse(evt.data);
                  if(signal.sdp) { 
                      peerConn.setRemoteDescription(new RTCSessionDescription(signal.sdp));
                      alert("desc");
                  } else { 
                      peerConn.addIceCandidate(new RTCIceCandidate(signal.candidate));
                      alert("ice");
                  }
              }
          } catch(e) {
              console.log(e.message);
          }
  </code></pre>
  
  <p>In Chrome this errors out with:</p>
  
  <pre><code>Uncaught Error: InvalidStateError: DOM Exception 11
  </code></pre>