title: Firefox element.event works but element.addEventlistener does not
body: <p>I am having some problems with <code>addEventListener</code> in Firefox.
  I have an iframe on my site for a WYSIWYG area I built myself. </p>
  
  <p>I want the iframe to look more like a normal textarea so I want a border around the iframe on focus. First tp (textpreview) is found like this (and works well):</p>
  
  <pre><code>var tp = document.getElementById('iframe-textpreview');
  var iframe = tp;    
  
  if(tp.contentDocument){ // normal
      tp = tp.contentDocument;
  }
  else if(tp.contentWindow){ // old IE
      tp = tp.contentWindow.document; 
  }
  //Open and close for Firefox
  tp.open();
  tp.close();
  tp.designMode = 'on';
  </code></pre>
  
  <p>Then I try to attach an <code>eventlistener</code> and log when the event fires. This works in Chrome, Opera and the most recent IE but not in Firefox:</p>
  
  <pre><code>//Doesn't work in Firefox
  tp.body.addEventListener('focus', function(){ console.log('focus...')});
  tp.body.addEventListener('blur', function(){ console.log('blur...')});
  </code></pre>
  
  <p>This does work however:</p>
  
  <pre><code>//Firefox
  tp.body.onfocus = function(){ console.log('focus...')};
  tp.body.onblur = function(){ console.log('blur...')};
  </code></pre>
  
  <p>I have cleared the cache on Firefox and tried with another computer, still no luck to get the first option working.</p>