title: which javascript files are NOT being used on page load
body: <p>Is it possible to find out which javascript files are NOT used on a web page without having to add console logs or debug or removing them to see if things break?</p>
  
  <p>I'm looking for a tool, or a command line script or firefox plugin etc.</p>
  
  <p>For example, let's say I have these included in the header:</p>
  
  <pre><code>&lt;script type="text/javascript" src="js/jquery.js"&gt;&lt;/script&gt;
  &lt;script type="text/javascript" src="js/functions.js"&gt;&lt;/script&gt;
  &lt;script type="text/javascript" src="js/validation.js"&gt;&lt;/script&gt;
  &lt;script type="text/javascript" src="js/something.js"&gt;&lt;/script&gt;
  </code></pre>
  
  <p>On the page, calls are only made to functions in <code>functions.js</code>, <code>validation.js</code> and <code>jquery.js</code>. How can I know that <code>something.js</code> is not used and therefore can be safely removed from the header?</p>
  
  <p>I've tried rooting through things like FireBug, chrome's console, yslow and server logs, but these all tell me which scripts have been loaded, i.e. all of them, not which ones have been used.</p>