Click inside either of the two TextBox controls below or click the link to see
a demonstration of the BalloonPopupExtender control.
The BalloonPopupExtender control displays a popup which can contain any content. For example, you can use
the BalloonPopupExtender to display help information when you move focus to a TextBox control.
The BalloonPopupExtender supports three different styles: Balloon, Rectangle, and Custom. You can select
among three different sizes for the popup: Small, Medium, and Large. If you set the BalloonPopup
style to the value Custom then you can define a custom appearance for the BalloonPopup. In that
case, you also need to set the CustomCssUrl property to point to a custom style sheet.
This control can be set to 5 positions - TopLeft, TopRight, BottomLeft, BottomRight and Auto. If
you select the value Auto then the position of the BalloonPopup is determined automatically based
on available space.
You can set the BalloonPopExtender to be triggered by the MouseOver, Focus or Click events. The control is
hidden automatically when you click outside the Balloon Popup.
The BalloonPopupExtender is initialized with this code. The italic properties
<ajaxToolkit:BalloonPopupExtender ID="PopupControlExtender2" runat="server"