title: Sys is undefined
body: <p>I have an ASP.Net/AJAX control kit project that i am working on.  80% of the time there is no problem.  The page runs as it should.  If you refresh the page it will sometimes show a javascript error "Sys is undefined".</p>
  
  <p>It doesn't happen all the time, but it is reproducible.  When it happens, the user has to shut down their browser and reopen the page.</p>
  
  <p>This leads me to believe that it could be an IIS setting.</p>
  
  <p>Another note.  I looked at the page source both when I get the error, and when not.  When the page throws errors the following code is missing:</p>
  
  <pre><code>&lt;script src="/ScriptResource.axd?d=EAvfjPfYejDh0Z2Zq5zTR_TXqL0DgVcj_h1wz8cst6uXazNiprV1LnAGq3uL8N2vRbpXu46VsAMFGSgpfovx9_cO8tpy2so6Qm_0HXVGg_Y1&amp;amp;t=baeb8cc" type="text/javascript"&gt;&lt;/script&gt;
  &lt;script type="text/javascript"&gt;
  //&lt;![CDATA[
  if (typeof(Sys) === 'undefined') throw new Error('ASP.NET Ajax client-side framework failed to load.');
  //]]&gt;
  &lt;/script&gt;
  </code></pre>