title: Jquery ajaxStart doesnt get triggered
body: <p>This code</p>
  
  <pre><code>$("#loading").ajaxStart(function() {
          alert("start");
          $(this).show();
      });
  </code></pre>
  
  <p>in my mark-up</p>
  
  <pre><code>&lt;div style="text-align:center;"&gt;&lt;img id="loading" src="../images/common/loading.gif" alt="" /&gt;&lt;/div&gt;
  </code></pre>
  
  <p>Here is the full ajax request:</p>
  
  <pre><code>$.ajax({
          type: "POST",       
  
          url: "http://localhost/WebServices/Service.asmx/GetResults",
  
          data: jsonText,
          contentType: "application/json; charset=utf-8",
          dataType: "json",
          success: function(response) {
  
              var results = (typeof response.d) == 'string' ? eval('(' + response.d + ')') : response.d;
              PopulateTree(results);
          },
  
          error: function(xhr, status, error) {
              var msg = JSON.parse(xhr.responseText);
              alert(msg.Message);
  
  
          }
      });
  
  $("#loading").ajaxStart(function() {
          alert("start");
          $(this).show();
      });
  
      $("#loading").ajaxStop(function() {
          alert("stop");
          $(this).hide();
          $("#st-tree-container").show();
  
      });
  </code></pre>
  
  <p>never fires alert "start" even though the gif is shown to rotate. AjaxStop gets triggered as expected.
  Any ideas why?</p>