title: HTML Video autoplay not working in Firefox
body: <p>I have a website built with bootstrap and loading video in a dialog:</p>
  
  <pre><code>&lt;video width="760" style="background-color: white;" preload controls autoplay&gt;
      &lt;source src="....." type="video/mp4" /&gt;
  &lt;/video&gt;
  </code></pre>
  
  <p>Shows and works fine in IE, Chrome and Safari.
  In Firefox auto play worked a few times, and now does not work at all.
  No errors in console and video plays just fine manually using controls.</p>
  
  <p>I have also tried script approach (without autoplay attribute):</p>
  
  <pre><code>oncanplay="$(this)[0].play()"
  </code></pre>
  
  <p>And works flawlessly on all browsers except Firefox.</p>
  
  <p>Can anyone see what could be wrong?</p>