Model Popup on Loading ASP.Net Page

<%@ Register assembly="AjaxControlToolkit" namespace="AjaxControlToolkit" tagprefix="cc1" %>

<style type="text/css">

        .modalBackground

        {

             background-color:#3E3535;

                    filter:alpha(opacity=60);

                    opacity:0.60;

        }

    </style>

<script language="javascript" type="text/javascript">

    function pageLoad() {

        ShowPopup();

        setTimeout(HidePopup, 2000);

    }

    function ShowPopup() {

        $find('modalpopup').show();

        //$get('Button1').click();

    }

    function HidePopup() {

        $find('modalpopup').hide();

        //$get('btnCancel').click();

    }

</script>

</ContentTemplate></asp:updatepanel>

            

       <asp:Panel ID="pnlProgress" runat="server" Height="55px" Width="321px"  

        BackImageUrl="../Images/Loading.jpg" style=" display:none;"  >

            <div  >

                <table  width="100%" style="height: 55px; width: 77px;">

                    <tbody>

                        <tr>

                            <td style="text-align: right">

                                <img alt="" src="../Images/indicator-big.gif" />

                            </td>

                        </tr>

                    </tbody>

                </table>

            </div>

        </asp:Panel>

       

       

       

       

        <cc1:ModalPopupExtender ID="mpeProgress" runat="server" TargetControlID="pnlProgress" PopupControlID="pnlProgress" BackgroundCssClass="modalBackground" DropShadow="false" />

       

       

        </div>

       

          <script type="text/javascript">

        Sys.Net.WebRequestManager.add_invokingRequest(onInvoke);

        Sys.Net.WebRequestManager.add_completedRequest(onComplete);

        function onInvoke(sender, args)

        {

            $find('<%= mpeProgress.ClientID %>').show();

        }

        function onComplete(sender, args)

        {

            $find('<%= mpeProgress.ClientID %>').hide();

        }

        function pageUnload()

        {

            Sys.Net.WebRequestManager.remove_invokingRequest(onInvoke);

            Sys.Net.WebRequestManager.remove_completedRequest(onComplete);

        }

    </script> 

  

  

    </form>