title: 'Sys.WebForms.PageRequestManager' is null or not an object
body: <p>Hi I have an aspx page in which i have the following code    </p>
  
  <pre><code>  &lt;asp:ScriptManager ID="scriptManager" runat="server" AsyncPostBackTimeout="500" EnablePageMethods="true"&gt;
              &lt;/asp:ScriptManager&gt;
  
              &lt;script type="text/javascript"&gt;
            Sys.Application.add_init(BeginRequestHandler);
            Sys.Application.add_init(EndRequestHandler);
  
            Sys.WebForms.PageRequestManager.getInstance().add_beginRequest(BeginRequestHandler);
            Sys.WebForms.PageRequestManager.getInstance().add_endRequest(EndRequestHandler);
            function BeginRequestHandler(sender, args) {
                AsynProcessing('block', 'AlertDiv', 'ProcessingImage');
            }
            function EndRequestHandler(sender, args) {
                AsynProcessing('none', 'AlertDiv', '');
            }
            function AsynProcessing(visstring, elem, img) {
                var adiv = $get(elem);
                adiv.style.display = visstring;
                adiv.image = img;
            }
  </code></pre>
  
  <p>But the page is throwing a javascrip error as 'Sys.WebForms.PageRequestManager' is null or not an object. I have placed the   below the scriptmanager tag. I even ried adding </p>
  
  <pre><code>&lt;xhtmlConformance  mode="Transitional"/&gt;
  </code></pre>
  
  <p>in the   section of web.config.But still getting the same error.<br>
  Any help is much appreciated. Thanks in advance</p>