TextBoxWatermark is an ASP.NET AJAX extender that can be attached to an ASP.NET TextBox control to get "watermark" behavior. When a watermarked TextBox is empty, it displays a message to the user with a custom CSS style. Once the user has typed some text into the TextBox, the watermarked appearance goes away. The typical purpose of a watermark is to provide more information to the user about the TextBox itself without cluttering up the rest of the page.
WatermarkTextBox Server Properties
The properties in italics
<ajaxToolkit:TextBoxWatermarkExtender ID="TBWE2" runat="server"
WatermarkText="Type First Name Here"
- TargetControlID - The ID of the TextBox to operate on
- WatermarkText - The text to show when the control has no value
- WatermarkCssClass - The CSS class to apply to the TextBox when it has no value (e.g. the watermark text is shown).