We can design a popup window with a zooming effect with a blur backround using modalpopupextender on the click event of the LinkButton or Anchor tag or Button.
<asp:LinkButton ID="lnkInvite1" runat="server" CssClass="body">Invite</asp:LinkButton>
<cc1:ModalPopupExtender ID="ModalPopupInvitationMail" runat="server" TargetControlID="lnkInvite1" PopupControlID="PanelInvitationMail" BackgroundCssClass="modalBackground" OkControlID="imgClose" CancelControlID="btnCancelInvitation" PopupDragHandleControlID=""></cc1:ModalPopupExtender>
<asp:Panel id="Panel1" runat="server"> ///Your Content here </asp:Panel>And last but not least don't forget to register Ajax Control Toolkit by using the following code:<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="cc1" %>
<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="cc1" %>