title: Find the "potential" width of a hidden element
body: <p>I'm currently extending the <a href="http://www.gmarwaha.com/blog/2007/08/23/lavalamp-for-jquery-lovers/" rel="noreferrer">lavalamp plugin</a> to work on dropdown menus but I've encountered a small problem. I need to know the <code>offsetWidth</code> of an element that is hidden. Now clearly this question makes no sense, rather what I'm looking for is the <code>offsetWidth</code> of the element were it not hidden.</p>
  
  <p>Is the solution to show it, grab the width, then hide again? There must be a better way...</p>