title: iframe onclick not working
body: <p>i have 2 iframe(embed) element. Trying to show an alert window before playing the video, but no alert window showing. This is what i'm trying to do.</p>
  
  <p>this is html (2 iframe)</p>
  
  <pre><code>&lt;iframe width="450" height="253" src="https://www.youtube.com/embed/ROtv13CqjzU?feature=oembed" frameborder="0" allowfullscreen="" style="width: 100%; height: 100%; z-index: 1; position: relative;" __idm_id__="490590210"&gt;&lt;/iframe&gt;
  &lt;iframe src="https://player.vimeo.com/video/235638223" width="450" height="190" frameborder="0" title="AUTOMATICA - Robots Vs. Music - Nigel Stanford" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen="" style="width: 100%; height: 100%; z-index: 1; position: relative;"
  __idm_id__="490590209"&gt;&lt;/iframe&gt;
  </code></pre>
  
  <p>this is js</p>
  
  <pre><code>var iframee = document.querySelectorAll("iframe");
  iframee[0].onclick = function(){
  alert(this);
  }
  </code></pre>
  
  <p>any idea how to do this?</p>