title: removing an iframe from the dom
body: <p>I'm simply trying to remove an <code>iframe</code> from the DOM using a chrome extension I'm building.</p>
  
  <p>This code isn't removing the <code>iframe</code>.</p>
  
  <pre><code>var frame = document.getElementById( "tracking" ); 
  frame.parentNode.removeChild( frame );
  </code></pre>
  
  <p>My manifest file is set up correctly. I'm able to access other elements on the page like this:</p>
  
  <pre><code>var bg = document.getElementById( "someId" ); 
  bg.parentNode.removeChild( bg );
  </code></pre>
  
  <p>Why can't I remove the <code>iframe</code>?</p>