title: How to get the source element id in endRequest Method?
body: <p><br>
  how do i get the id of element that caused postback in add_endRequest?<br>
  example<br>
     //wire the End Request process,</p>
  
  <pre><code>Sys.WebForms.PageRequestManager.getInstance().add_endRequest(requestComplete_Handler)
  
      //will be called after the async request completes.
      function requestComplete_Handler(sender, args)
      {
          var panel = sender._postBackSettings.sourceElement.id;
          switch (panel)
          {
              case "&lt;%=upSubAccount.ClientID %&gt;":
                  __doPostBack('&lt;%=upAllocationChart.ClientID%&gt;');
                  break;
              case "&lt;%=upAllocationChart.ClientID%&gt;" :   
                 __doPostBack('&lt;%=upTotal.ClientID %&gt;');
              break;
          }
      }
  </code></pre>
  
  <p>although this works but no every time <br>
  <code>sender._postBackSettings.sourceElement.id;</code><br>
  thanks.</p>