I given my coding for a modal popup using AJAX. The problem is when I click the button, the popup is not displaying instead, it is just blinking once. Look at my code and tell me what is the problem with it.
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:LinkButton ID="LinkButton1" runat="server">Login</asp:LinkButton>
<asp:Panel ID="Panel1" runat="server" Width="241px" Style="display:none" >
<table style="border-style: inherit; border-width: thin; width:100%;">
<tr>
<td class="style2">Username</td>
<td><asp:TextBox ID="TextBox1" runat="server"></asp:TextBox></td>
</tr>
<tr>
<td class="style3">Password</td>
<td class="style1"><asp:TextBox ID="TextBox2" runat="server"></asp:TextBox></td>
</tr>
<tr>
<td class="style2"><asp:Button ID="Button1" runat="server" Text="Signin" /> </td>
<td><asp:Button ID="Button2" runat="server" Text="Cancel" /></td>
</tr>
</table>
</asp:Panel>
<ajaxTK:ModalPopupExtender ID="ModalPopupExtender" runat="server"
TargetControlID="LinkButton1"
PopupControlID="Panel1"
OkControlID="Button1"
CancelControlID="Button1"
BackgroundCssClass="modepop">
</ajaxTK:ModalPopupExtender>