title: In ion-content change the source of video tag via javascript is not working
body: <p>Code :</p>
  
  <pre><code>&lt;video  id='play_video' controls="controls"  width="100%" height="100%" autoplay="autoplay" webkit-playsinline="webkit-playsinline" class="videoPlayer"&gt;             
  &lt;source id='mp4Source' src="" type="video/mp4"/&gt;
   &lt;/video&gt;
  </code></pre>
  
  <p>Javascript</p>
  
  <pre><code>var player = document.getElementById('play_video');  
  var mp4Vid = document.getElementById('mp4Source');
  mp4Vid = "http://scontent-lht6-1.cdninstagram.com/t50.2886-16/10951700_1534409696814630_381716634_n.mp4";
  player.load();
  player.play();
  </code></pre>
  
  <p>Issue:
  video tag is inside ion-content.try to change the src of source tag via javascript is not working. what is the solution for this??</p>