title: Javascript: Adding attribute dynamically to the <html /> tag
body: <p>I'm trying to add FB xmlns attribute to the document's <code>&lt;html&gt;</code> tag (<code>&lt;html lang="en" xml:lang="en" xmlns="http://www.w3.org/1999/xhtml"&gt;</code>) dynamically.  For some reason adding it like below does not work:</p>
  
  <pre><code>htmltag  = document.getElementsByTagName ('html');
  htmltag[0].setAttribute("xmlns:fb","http://www.facebook.com/2008/fbml");");
  </code></pre>
  
  <p>How can I do it?</p>
  
  <p>Thanks!</p>
  
  <p>Update: No jquery or other lib is available.</p>