title: iFrame twitter follow button callback
body: <p>I am not able to get the callback to work for the twitter follow button using the iFrame version. Here is my code:</p>
  
  <pre><code>&lt;iframe allowtransparency="true" frameborder="0" scrolling="no"
          src="https://platform.twitter.com/widgets/follow_button.html?screen_name=gaur_aditya&amp;show_screen_name=true&amp;show_count=true"
          style="height:20px;"&gt;&lt;/iframe&gt;
  
  &lt;script src="//platform.twitter.com/widgets.js" type="text/javascript"&gt;&lt;/script&gt;
  &lt;script type="text/javascript"&gt;
      twttr.events.bind('follow', function(event) {
          console.log(event);
          var followed_user_id = event.data.user_id;
          var followed_screen_name = event.data.screen_name;
      });
  &lt;/script&gt;
  </code></pre>
  
  <p>I tried out <a href="https://stackoverflow.com/a/8312716/593418">this</a> version which worked fine. But using the iFrame version I am not able to make it work. </p>