title: Add dynamical elements in a Iframe element than i create
body: <p>i have a litle problem if i create a dynamically IFRAME element and i agregate dynamically elements to the new iframe. It works If i do that:</p>
  
  <pre><code>var miiframe=document.getElementById("miiframe");
  var myElement=content.document.createElement("LABEL");
  myElement.innerHTML="blabla";
  miiframe.contentDocument.body.appendChild(myElement);
  </code></pre>
  
  <p>but if i do that doesn't works:<br /></p>
  
  <pre><code>var miiframe=content.document.createElement("IFRAME");
  miiframe.src="about:blank";
  document.body.appendChild(miiframe);
  var myElement=content.document.createElement("LABEL");
  myElement.innerHTML="blabla";
  miiframe.contentDocument.body.appendChild(myElement);
  </code></pre>
  
  <p>i see the iframe but i don't see the label element.
  The most courious is if before appendElement i do and alert it works!!!</p>
  
  <pre><code>var miiframe=content.document.createElement("IFRAME");
  miiframe.src="about:blank";
  document.body.appendChild(miiframe);
  var myElement=content.document.createElement("LABEL");
  myElement.innerHTML="blabla";
  alert("now works!!!");
  miiframe.contentDocument.body.appendChild(myElement);
  </code></pre>
  
  <p>With DIV element works but i want do that with IFRAME element!!!</p>
  
  <p>This code is for Firefox.
  Thanks!!</p>