title: How do I capture an iframe location url before it is loaded?
body: <p>I have an iFrame, not controlled by me, that has an initial known source url.  As links within the iframe are clicked, the url and content changes, but I want to capture that location change before it loads, and possibly even interrupt that load.</p>
  
  <p>I know I can capture an iframe's location data like so:</p>
  
  <pre><code>$('iframe').on('load',function() { var location = this.contentWindow.location.href; }
  </code></pre>
  
  <p>but is there a way capture the location before it loads, either with jQuery (preferred) or raw javascript?</p>