AJAX :: Set Position In ModalPopUp Extender?

i am using a datalist and in this i have a table when i am click on a button then popup display the table .but the position is fixed i want to change the position of popup dynamically as we have many button

Code is-

<table id="tb1" runat="server" width="50%">
<tr>
<td style="background-color: #A1CFF6; border-width: 1px; border-style: groove">
<asp:Image ID="imgClose" runat="server" ImageUrl="~/image/close.gif" ImageAlign="Right" />
<asp:Label ID="lblConInfo" runat="server" Text="Contact Information" Font-Bold="True"
Font-Size="Small" ForeColor="#678FE0"></asp:Label>
<br />
<asp:Label ID="lblName" runat="server" Text="Name:" Font-Bold="True"></asp:Label>
<asp:Label ID="lblFName" runat="server" Text='<%# Eval("c_Fname") %>'></asp:Label>
<asp:Label ID="lblCity" runat="server" Text="City:" Font-Bold="True"></asp:Label>
<asp:Label ID="lbl_city" runat="server" Text='<%# Eval("c_city") %>'></asp:Label>
<asp:Label ID="lblPin" runat="server" Text="PinCode:" Font-Bold="true"></asp:Label>
<asp:Label ID="lbl_PinCode" runat="server" Text='<%# Eval("c_pincod") %>'></asp:Label>
</td>
</tr></table>
<cc1:ModalPopupExtender ID="ModalPopupExtender1" runat="server" PopupControlID="tb1"
TargetControlID="btnEnquiry" BackgroundCssClass="modalBackground" CancelControlID="imgClose"
X="200" Y="200" Enabled="true">
</cc1:ModalPopupExtender>