title: Check what error value is in ajax callback
body: <p>How can I check what the error value returned is in ajax callback error : </p>
  
  <pre><code>$.ajax({
              url: "myurl",       
              type: 'POST',
              dataType : "text",
              data : ({
                  json : myjson
              }),
              success : function(data) {
  
              },
     error : function() {
                  alert ('error');
      } 
  
          });  
  </code></pre>