title: TypeError: $(...)[0] is undefined
body: <p>In my chat script an error occurs on the following lines:</p>
  
  <pre><code>$("#chatbox_"+chatboxtitle+" .chatboxcontent")
  .scrollTop($("#chatbox_"+chatboxtitle+" .chatboxcontent")[0].scrollHeight);
  setTimeout('$("#chatbox_"+chatboxtitle+" .chatboxcontent")
  .scrollTop($("#chatbox_"+chatboxtitle+" .chatboxcontent")[0].scrollHeight);', 100);
  </code></pre>