title: Setting percent % width of FB comments via CSS or JS: not working
body: <p>I'm trying to set the width in percent (80%) of the Facebook code.This doesn't work!
  First I tried via css but nothing has changed. It's always of default Facebook width (500px about).</p>
  
  <pre><code>&lt;div id="fb-root" style="width: 80%"&gt;&lt;/div&gt;
  &lt;script src="http://connect.facebook.net/it_IT/all.js#xfbml=1"&gt;&lt;/script&gt;
  &lt;fb:comments href="http://stackoverflow.com" num_posts="5" width="auto"&gt;&lt;/fb:comments&gt; 
  </code></pre>
  
  <p>So, I decided to use javascript and change it width when the user resizes the browser's window. So, if my width screen is 1000px, it has to be 1000px. But when I resize the browser's window to 756px, it has to change to 756px via Javascript on the width="..." of fb:comments. The error is from Firebug (Firefox 8): box[0] is undefined -> var boxwidth = box[0].getAttribute("width");.</p>
  
  <pre><code>&lt;script type="text/javascript"&gt;
      var box = document.getElementsByTagName("fb:comments");
      var boxwidth = box[0].getAttribute("width");
  
      alert("start...");
      alert("width of element 'box': "+boxwidth);
      alert("...end");
  
      /*resolution = screen.width;
      alert("Screen width: "+resolution);*/
  &lt;/script&gt; 
  </code></pre>
  
  <p>Is there a way to set dynamically the width of fb:comments? Thanks in advance.
  See you, Davide.</p>
  
  <p>PS. Sorry for my English mistakes, if i did some so....</p>