title: Cross domain ajax request success event doesn't fire
body: <p>Here is the scenario which is surprisingly simple:</p>
  
  <p>I send an ajax request which targets a different domain:</p>
  
  <pre><code>$(function(){
          $.ajax({
              url: "http://www.drivescheduler.com/functions.php?function=getHighSchools&amp;code=" + $("#code").val(),
              type: 'get',
              async: true,
              crossDomain: true,
              beforeSend: function(xhr){
                  xhr.withCredentials = true;
              },
              success: function(x, status, xhr){
                  alert();
              }
          });
      });
  </code></pre>
  
  <p>On the domain which receives the ajax request, I've properly configured CORS headers:</p>
  
  <pre><code>header('Access-Control-Allow-Origin: http://temp.jfdin.net');
  header('Access-Control-Allow-Methods: POST');
  header('Access-Control-Allow-Headers: Content-MD5, X-Alt-Referer');
  header('Access-Control-Allow-Credentials: true');
  header("Content-Type: application/json; charset=utf-8");
  </code></pre>
  
  <p>And I can see the request being sent and the proper response being received through Chrome Debug Tools, but I get no <code>alert()</code>.<br>
  In other words, the success event never gets fired.<br>
  Why is that and how can I fix it?</p>