In this code we will see how to use Ajax Ballon Pop up Extender
for this we have to download the ajax control tool kit and then use the following code.
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<asp:Panel ID="Panel1" runat="server" BackColor="#FF7F50">
<b>Hey
I am simple TextBox with BallonPopup</b>
<br />
<asp:BalloonPopupExtender ID="BalloonPopupExtender1" runat="server" TargetControlID="TextBox1" BalloonPopupControlID="Panel1" BalloonSize="Medium"
UseShadow="true" >
</asp:BalloonPopupExtender>
</asp:Panel>