title: ASP.NET MVC jQuery ajax call returns status code -504 instead of 5xx on Safari 4
body: <p>My MVC controllers return 5xx status codes to indicate errors when called using jQuery ajax. This works great on IE8 and Firefox.</p>
  
  <p>However, on my copy of Safari 4.0.5 running on Vista, this breaks. It looks like Safari is translating my 5xx status codes to -504. </p>
  
  <p>Successful ajax calls work fine, and I've already tried uninstalling and reinstalling Safari.</p>
  
  <p>Does anyone know what this status code means? I couldn't find any references to it online.</p>