title: Change iframe src using javascript/jquery without setting protocol
body: <p>I'm trying to use Javascript to change the src of an iframe. However, the source I am trying to change it to is: </p>
  
  <pre><code> //embed.expertfile.com/v1/expert/
  </code></pre>
  
  <p>However, when I attempt to do that using</p>
  
  <pre><code>document.getElementById('iframe2').src = url;
  </code></pre>
  
  <p>It will consistently add the site URL to it. So the end result would be:</p>
  
  <pre><code>http://stackoverflow.com/questions/ask//embed.expertfile.com/v1/expert/
  </code></pre>
  
  <p>Is there anyway to prevent the current site URL from being added to the src?</p>