title: jQuery $.ajax fails in ie9/FF when using statusCode, fix?
body: <p>Submitting the following $.ajax, which is indeed executing but fails silently without any error. IE9 dev tools don't spring an error and fiddler shows no traffic.</p>
  
  <p>I can confirm the code does indeed execute since the "processing" bit does appear on the screen. However the rest seems to just fail. I am <em>not</em> doing x-domain.</p>
  
  <pre><code>$('.signupMsg').html("&lt;img src='/assets/img/load-black.gif' /&gt; Processing...");
  var data = $('#emailForm').serialize();
  $.ajax({
      url: 'https://example.com/proxy/emaillist',
      type: 'POST',
      data: data,
      statusCode: {
          200: function(msg) {
              $('.signupBlock').html("&amp;nbsp;&lt;br&gt;&lt;strong&gt;Thank you!&lt;/strong&gt;&lt;br&gt;You will be hearing from us soon.");
              $('#emailForm').remove();
          },
          500: function(msg) {
              $('.signupBlock').html("&amp;nbsp;&lt;br&gt;&lt;strong&gt;Something went wrong.&lt;/strong&gt;&lt;br&gt;Sorry about that, please &lt;a href='/'&gt;refresh&lt;/a&gt; and try again.");
              $('#emailForm').remove();
          },
              404: function(msg) {
                      $('.signupBlock').html("&amp;nbsp;&lt;br&gt;&lt;strong&gt;Something went wrong.&lt;/strong&gt;&lt;br&gt;Sorry about that, please &lt;a href='/'&gt;refresh&lt;/a&gt; and try again.");
                      $('#emailForm').remove();
              },
          503: function(msg) {
              $('.signupBlock').html("&amp;nbsp;&lt;br&gt;&lt;strong&gt;Server temporarily down.&lt;/strong&gt;&lt;br&gt;Sorry about that, please &lt;a href='/'&gt;refresh&lt;/a&gt; and try again.");
              $('#emailForm').remove();
          },
          400: function(msg) {
              $('.signupMsg').html("&lt;span style='color:red'&gt;Email validation failed, please try again.&lt;/span&gt;");
          }
      }                   
  </code></pre>
  
  <p>});</p>
  
  <p>Using jQ 1.7.2. The code executes fine in Google Chrome but fails in IE7-9 and FF. Is statusCode not supported in older browsers?</p>
  
  <p>Or should I just switch to SuperAgent for code response support? <a href="http://visionmedia.github.com/superagent/" rel="nofollow">http://visionmedia.github.com/superagent/</a></p>