STUN/TURN server connectivity test

var res = id('result');

id('button').onclick = function(){
	res.innerHTML = 'Checking TURN Server...';
  var url = 'turn:'+id('url').value+':'+id('port').value,
  		useUDP = id('udp').checked;
  url +='?transport=' + (useUDP ? 'udp': 'tcp');
  checkTURNServer({
      urls: url,
      username: id('name').value, 
      credential: id('pass').value
  }, id('time').value).then(function(bool){
  		if(bool)
         res.innerHTML = 'Yep, the TURN server works...';
      else
         throw new Error('Doesn\'t work');
  }).catch(function(e){
  	 console.log(e);
     res.innerHTML = 'TURN server does not work.';
  });
};


function checkTURNServer(turnConfig, timeout){ 
	console.log('turnConfig: ', turnConfig);
  return new Promise(function(resolve, reject){

    setTimeout(function(){
        if(promiseResolved) return;
        resolve(false);
        promiseResolved = true;
    }, timeout || 5000);

    var promiseResolved = false
      , myPeerConnection = window.RTCPeerConnection || window.mozRTCPeerConnection || window.webkitRTCPeerConnection   //compatibility for firefox and chrome
      , pc = new myPeerConnection({iceServers:[turnConfig]})
      , noop = function(){};
    pc.createDataChannel("");    //create a bogus data channel
    pc.createOffer(function(sdp){
      if(sdp.sdp.indexOf('typ relay') > -1){ // sometimes sdp contains the ice candidates...
        promiseResolved = true;
        resolve(true);
      }
      pc.setLocalDescription(sdp, noop, noop);
    }, noop);    // create offer and set local description
    pc.onicecandidate = function(ice){  //listen for candidate events
      if(promiseResolved || !ice || !ice.candidate || !ice.candidate.candidate || !(ice.candidate.candidate.indexOf('typ relay')>-1))  return;
      promiseResolved = true;
      resolve(true);
    };
  });   
}


function id(val){
	return document.getElementById(val);
}

#url{
  width: 250px;
}
#port{
  width: 70px;
}

<h1>
 Test TURN server
</h1>
<div>
TURN URL: <input id='url' placeholder='example.com  or  xxx.yyy.rrr.ddd'  />
Port: <input type='number' value='3478' id='port' placeholder='enter a port number' />
</div>
<div>
Transport: <input type="radio" name="transport" id="tcp" value="tcp" /> TCP
<input type="radio" name="transport" id="udp" value="udp" checked/>UDP
</div>

<div>
Username: <input id="name" placeholder="turn username" />
</div>
<div>
password: <input id="pass" placeholder="turn password" />
</div>

<div>
checking Timeout: <input type='number'  id="time" placeholder="wait time  before checking timeout" value=5000 />
</div>
<div>
<button id='button'>
Check TURN Server
</button>
</div>

<h4 id='result'></h4>