title: load event for iframe does not fire in IE
body: <p>I've created an <code>iframe</code> in my page here is it's code:  </p>
  
  <pre><code>var frame = document.createElement('iframe');
  frame.setAttribute('src','');
  document.body.appendChild(frame);
  if(document.addEventListener){
      frame.addEventListener('load', callback, false);
  } else {
      frame.attachEvent('onload', callback);
  }
  
  function callback(){
      alert('test');
  }
  </code></pre>
  
  <p>It works fine in FF but no thing alerted in IE, why?<br>
  Note that I use IE10 in win8</p>