anchor.diff:  	}
   	else if (window.URL) video.src = window.URL.createObjectURL(stream);
   	else video.src = stream;
  -	myButton = document.getElementById('buttonSnap');
  -	if (myButton) myButton.disabled = false;
  -	myButton = document.getElementById('buttonStop');
  -	if (myButton) myButton.disabled = false;
  +	buttonState(snapButton, false);
  +	buttonState(stopButton, false);
   }
   
   function start()
  
positive.code: 	  	</div>
  		<div class="panel-body">
  			<p><video id="video" autoplay="autoplay" class="img-thumbnail"></video></p>
  			<p><input type="button" id="buttonSnap" value="Prendre une photo" disabled="disabled" onclick="snapshot()" /></p>
  			<p>
  			<input type="button" id="buttonStart" value="Démarrer" disabled="disabled" onclick="start()" />
  			<input type="button" id="buttonStop" value="Arrêter" disabled="disabled" onclick="stop()" />
  			</p>
  			<p><canvas id="canvas" class="img-thumbnail"></canvas></p>
  		</div>
  
negative.code: var canvas = document.getElementById('canvas');
  var videoStream = null;
  var preLog = document.getElementById('preLog');
  var stopButton = document.getElementById('buttonStop');
  var snapButton = document.getElementById('buttonSnap');
  var startButton = document.getElementById('buttonStart');
  
  function buttonState(b, s) {
  	if (b) b.disabled = s;
  }
  
  function log(text)
  {
  