diff --git a/index.html b/index.html
index 5440435a..46ade8a8 100644
--- a/index.html
+++ b/index.html
@@ -26,9 +26,36 @@ textarea {
 </div>
 <script>
 
+// miscs
+
+let log = msg => {
+  document.getElementById('div').innerHTML += msg + '<br>'
+  console.log(msg);
+}
+
+
+//
+let pc = new RTCPeerConnection({iceServers: [{urls: 'stun:stun.l.google.com:19302'}]})
+
 var localSessionDescription = ""
 var remoteSessionDescription = ""
 
+
+var conn = new WebSocket(`ws://${location.host}/ws`);
+conn.onopen = () => {
+  log("WebSocket is opened");
+}
+
+conn.onerror = error => {
+  log(`Websocket error: ${error}`);
+}
+
+conn.onmessage = e => {
+  console.log(e.data);
+  // e.data in json
+}
+
+
 function postSession(session) {
   if (session == "") {
     return;
@@ -46,48 +73,23 @@ function postSession(session) {
 
 }
 
-let pc = new RTCPeerConnection({
-  iceServers: [
-    {
-      urls: 'stun:stun.l.google.com:19302'
-    }
-  ]
-})
-let log = msg => {
-  document.getElementById('div').innerHTML += msg + '<br>'
-}
-
-
-const dataChannelOptions = {
-  ordered: false, // do not guarantee order
-  maxPacketLifeTime: 3000, // in milliseconds
-};
 
+// input channel
 let inputChannel = pc.createDataChannel('foo')
-inputChannel.onclose = () => console.log('inputChannel has closed')
-inputChannel.onopen = () => console.log('inputChannel has opened')
-inputChannel.onmessage = e => log(`Message from DataChannel '${inputChannel.label}' payload '${e.data}'`)
-
-pc.ontrack = function (event) {
-  var el = document.createElement(event.track.kind)
-  el.srcObject = event.streams[0]
-  el.autoplay = true
-  el.controls = true
-
-  document.getElementById('remoteVideos').appendChild(el)
+inputChannel.onclose = () => {
+  log('inputChannel has closed');
 }
 
-pc.onicecandidate = event => {
-  if (event.candidate === null) {
-    var session = btoa(JSON.stringify(pc.localDescription));
-    localSessionDescription = session;
-    postSession(session)
-  }
+inputChannel.onopen = () => {
+  log('inputChannel has opened');
 }
 
-pc.createOffer({offerToReceiveVideo: true, offerToReceiveAudio: true}).then(d => pc.setLocalDescription(d)).catch(log)
+inputChannel.onmessage = e => {
+  log(`Message from DataChannel '${inputChannel.label}' payload '${e.data}'`);
+}
 
 
+// Input handler
 keyState = {
   // controllers
   a: false,
@@ -136,20 +138,6 @@ document.body.onkeyup = function(e){
   setState(e, false);
 };
 
-
-window.startSession = () => {
-  let sd = remoteSessionDescription
-  if (sd === '') {
-    return alert('Session Description must not be empty')
-  }
-
-  try {
-    pc.setRemoteDescription(new RTCSessionDescription(JSON.parse(atob(sd))));
-  } catch (e) {
-    alert(e);
-  }
-}
-
 var timer = null;
 function sendInput() {
   // prepare key
@@ -204,5 +192,53 @@ pc.oniceconnectionstatechange = e => {
 
 }
 
+
+
+// stream channel
+pc.ontrack = function (event) {
+  var el = document.createElement(event.track.kind)
+  el.srcObject = event.streams[0]
+  el.autoplay = true
+  el.controls = true
+
+  document.getElementById('remoteVideos').appendChild(el)
+}
+
+
+// candidate packet from STUN
+pc.onicecandidate = event => {
+  if (event.candidate === null) {
+    // var session = btoa(JSON.stringify(pc.localDescription));
+    // localSessionDescription = session;
+    // postSession(session)
+  }
+}
+
+
+// create SDP
+pc.createOffer({offerToReceiveVideo: true, offerToReceiveAudio: true}).then(d => {
+  pc.setLocalDescription(d, () => {
+    // send to ws
+    session = btoa(JSON.stringify(pc.localDescription));
+    localSessionDescription = session;
+    conn.send(JSON.stringify({"id": "sdp", "data": session}));
+  });
+
+}).catch(log);
+
+
+window.startSession = () => {
+  let sd = remoteSessionDescription
+  if (sd === '') {
+    return alert('Session Description must not be empty')
+  }
+
+  try {
+    pc.setRemoteDescription(new RTCSessionDescription(JSON.parse(atob(sd))));
+  } catch (e) {
+    alert(e);
+  }
+}
+
 </script>
 </html>
diff --git a/main.go b/main.go
index 428c3a4d..f514176a 100644
--- a/main.go
+++ b/main.go
@@ -75,12 +75,15 @@ func ws(w http.ResponseWriter, r *http.Request) {
 	}
 	defer c.Close()
 
+	log.Println("new connection")
 	webRTC := webrtc.NewWebRTC()
 	localSession, err := webRTC.StartClient(width, height)
 	if err != nil {
 		log.Fatalln(err)
 	}
 
+	log.Println("new connection2")
+
 	// streaming game
 	// imageChannel := make(chan *image.RGBA, 100)
 	// go screenshotLoop(imageChannel, webRTC)