title: Update Panel AsyncPostback Trigger not working in IE
body: <p>In my application <strong>the AsyncPostback trigger</strong> of update panel is <strong>not</strong> working in <strong>IE 9 and IE 10</strong> but working in IE 8 and postbacktrigger is also working in all IE version.</p>
  
  <p>This give error </p>
  
  <blockquote>
    <p>Sys.WebForms.PageRequestManagerParserErrorException: The message
    received from the server could not be parsed.</p>
  </blockquote>
  
  <p>I have tried several thing before posting this issue :</p>
  
  <ul>
  <li>async = true in page tag</li>
  <li>registering the postback on page load (this cannot be used as update panel is throughout the system)</li>
  <li>allowing async in web config</li>
  </ul>
  
  <p></p>
  
  <pre><code>&lt;asp:UpdatePanel runat="server"&gt;
                                     &lt;ContentTemplate&gt;
                                         &lt;cc:BinNumberMultiDropDown runat="server" TabIndex="3"    ProgramTrue="true" ID="ddl_bin_number"
                                             CssClass="multiselect"&gt;
                                         &lt;/cc:BinNumberMultiDropDown&gt;
                                         &lt;asp:RequiredFieldValidator ID="rfv_ddl_bin_number" runat="server"    ControlToValidate="ddl_bin_number" ValidationGroup="vg_rate"    Display="Dynamic"
                                             SetFocusOnError="true"&gt;&lt;/asp:RequiredFieldValidator&gt;
                                     &lt;/ContentTemplate&gt;
                                     &lt;Triggers&gt;
                                         &lt;asp:AsyncPostBackTrigger ControlID="ddl_program" EventName="SelectedIndexChanged" /&gt;
                                     &lt;/Triggers&gt;
                                 &lt;/asp:UpdatePanel&gt;
  </code></pre>
  
  <p>Please suggest me with the solution</p>
  
  <p><strong>I also found that this error is appearing only in Winodws 8 systems</strong> </p>