title: Ajax with JQuery: 200 ok, but not “success”
body: <p>I'm facing the same issue, while trying for cross-domain request. Situation is strange, my data is getting loaded while hit the requested url directly on browser, the strange part is, this gets loaded if requested using jquery ajax as well, 
  but not on firebug <strong>console</strong>, but on firebug <strong>net</strong> tab. 
  Console prints: 
  Sample of error data: <em>parsererror</em> {while json data is well-formed and formatted, checked on json validators}</p>
  
  <pre><code>readyState: 4 status: 200 responseText: undefined
  </code></pre>
  
  <p><strong>Net</strong> tab loads all the data in <strong>response</strong> and <strong>json</strong> sub-tab</p>
  
  <p>My sample code is: </p>
  
  <pre><code>function fetchJsonData() {
  $.ajax({
      type: 'POST',
      url: 'http://www.meilleurmobile.com/comparateur/resultats-comparateur-json.do',
      data: 'monthDur%5B0%5D=45.75&amp;monthDur%5B1%5D=45.75&amp;monthDur%5B2%5D=45.75&amp;monthDur%5B3%5D=45.75&amp;monthDur%5B4%5D=45.75&amp;monthDur%5B5%5D=45.75&amp;monthDur%5B6%5D=45.75&amp;monthDur%5B7%5D=45.75&amp;monthDur%5B8%5D=45.75&amp;monthDur%5B9%5D=45.75&amp;monthDur%5B10%5D=45.75&amp;monthDur%5B11%5D=45.75&amp;numSms=1000&amp;dataVolume=1000&amp;withoutMobile=-1&amp;commitmentDuration=-1',
      async: false,
      cache: false,
      //contentType: 'application/json; charset=utf-8',
      crossDomain: true,
      dataType: 'jsonp',
      error: function( xhr,err ) {
          console.log( 'Sample of error data:', err );
          console.log("readyState: "+xhr.readyState+"\nstatus: "+xhr.status+"\nresponseText: "+xhr.responseText);
      },
      success: function( data ) {
          if (console &amp;&amp; console.log) {
              console.log( 'Sample of data:', data.slice(0,100) );
          }
      }
  })
  .done(function() { alert("success"); })
  .fail(function() { alert("error"); });
  </code></pre>
  
  <p>}</p>