ModalPopupExtender in AJAX

The ModalPopupExtender that this popup is attached to has a hidden TargetControl. The popup can be shown via server in code behind

<script type='text/javascript'>
function onCancel()
{
window.location = "../Pages/Home.aspx";
}
</script>



'<di v align="center">
<table align="center">
<tr>
<td align="center">

<br />
<asp:LinkButton ID="LinkButton1" runat="server" Text="Choose the Access Permission"></asp:LinkButton><br />
<br />
<div>
<br />
<asp:Panel ID="Panel1" runat="server" CssClass="modalPopup" Style="display: none" Width="233px">
<br />
<br />
<asp:Label ID="Label1" runat="server" Text="Access Permission" SkinID="HeaderLabel"></asp:Label>
<br />
<br />
<asp:Label ID="Label2" runat="server" Text="Access for :"></asp:Label>
<asp:DropDownList ID="ddlAccessFor" runat="server" AutoPostBack="True"
onselectedindexchanged="ddlAccessFor_SelectedIndexChanged" Width="140px">
</asp:DropDownList>
<br />
<br />
<div align="center">
<asp:Button ID="CancelButton" runat="server" Text="Cancel" />
</div>
<br />
<br />
</asp:Panel>
<br />
<ajaxToolkit:ModalPopupExtender ID="mdlPopup" runat="server"
TargetControlID="LinkButton1"
PopupControlID="Panel1"
BackgroundCssClass="modalBackground"
DropShadow="true"
CancelControlID="CancelButton"
OnCancelScript="onCancel()"
/>
</div>
</td>
</tr>
<tr><td>
<asp:Label ID="lblAccessfor" runat="server" ></asp:Label>
</td></tr>
</table>
<table>
<tr>
<td align="left" >
<asp:Label ID="lblFaculty" runat="server" Text="Faculty :" Visible="False"></asp:Label>
</td>
<td align="left">
<asp:DropDownList ID="ddlFaculty" runat="server" AutoPostBack="True"
onselectedindexchanged="ddlFaculty_SelectedIndexChanged" Visible="False"
Width="280px">
<asp:ListItem Value="0">-Select Faculty-</asp:ListItem>
</asp:DropDownList>
</td>
</tr>
<tr>
<td align="left" >
<asp:Label ID="lblDepartment" runat="server" Text="Department :" Visible="False"></asp:Label>
</td>
<td align="left">
<asp:DropDownList ID="ddlDepartment" runat="server" AutoPostBack="True"
onselectedindexchanged="ddlDepartment_SelectedIndexChanged"
Visible="False" Width="280px">
<asp:ListItem Value="0">-Select Department-</asp:ListItem>
</asp:DropDownList>
</td>
</tr>
<tr>
<td align="left" >
<asp:Label ID="lblAbbreviation" runat="server" Text="Abbreviation :"
Visible="False"></asp:Label>
</td >
<td align="left">
<asp:DropDownList ID="ddlAbbreviation" runat="server" AutoPostBack="True"
onselectedindexchanged="ddlAbbreviation_SelectedIndexChanged"
Visible="False" Width="180px">
<asp:ListItem Value="0">-Select Abbreviation-</asp:ListItem>
</asp:DropDownList>
</td>
</tr>
</table>
</div>

http://www.asp.net/ajax/ajaxcontroltoolkit/samples/modalpopup/modalpopup.aspx