title: Weird things happens when upgrading from jquery 1.3.2 to 1.9.1
body: <ul>
  <li>I have been using jquery 1.3.2, and I upgraded to 1.9.1
  What happens is that the ajax request that was reaching success, is reaching error now.
  I don't understand why, the status is 200, and the state is 4. Which means nothing wrong with the request. But why it is reaching the error?</li>
  </ul>
  
  <p>I made a work around as below but i don't like it. I would like to understand why it happened.I'm also afraid to have more problems like that.</p>
  
  <pre><code> $.ajax({
      type: "POST",
      url: "test.cgi",
      data: form_data,
      beforeSend: function(){
          $("#"+type+"_div").html("&lt;span class='LabelRed12'&gt;Loading , please wait..&lt;/span&gt;&lt;br/&gt;");
      },
      complete: function(){
  
      },
      success: function(html){
          $("#"+type +"_div").html(html);
  
      },
      error:function(xhr,err){
           if (xhr.readyState == 4) {
             if (xhr.status == 200) {
                  $("#"+type +"_div").html(xhr.responseText);
             } else
               alert("status is " + request.status);
           }
      }
      });
  </code></pre>