Does the HTML nodes in <iframe> support javascript in design mode? For the following code, dialog doesn't pop up when I click the <span>. My browser is FF 16.0.2. Is there any way to get an alert when clicking the span? 
<html>
  <body >
    <iframe id="myeditor" style="width:500px; height:170px;"></iframe><br><br>
    <script type="text/javascript">
      editor = document.getElementById("myeditor").contentWindow;
      editor.document.designMode="on";
      editor.document.open();
      editor.document.write('head <span onclick="alert(1)" style="border: solid 1px #666">click me</span> tail');
      editor.document.close();
    </script>
  </body>
</html>
Thanks for reading here. :D