title: "Unable to get value of the property 'appendChild': object is null or undefined" while appending script to IE
body: <p>When I try to append the following script to IE, I get this error:</p>
  
  <p>"Error: Unable to get value of the property 'appendChild': object is null or undefined"</p>
  
  <p>It works fine in Chrome, but when testing on IE9 this occurs. Can anyone tell me what the error is?</p>
  
  <pre><code>  // create script in document
      var fbScript = document.createElement("script");
      fbScript.type = "text/javascript";
  
      // make script source the facebook plugin
      fbScript.src = "http://connect.facebook.net/en_US/all.js#xfbml=1";
  
  
  
      // append script to appropriate tab
      document.getElementById('Tab' + tab_counter).appendChild(fbScript);
  </code></pre>