To use Ajax Watermark: 1. Set the attribute of the textbox to readonly in pageload e.g. if (!IsPostBack) { txtDateOfBirth.Attributes.Add("readonly", "readonly"); } 2. Use Ajax Calendar Extender to get the date e.g. <AjaxControlToolkit:CalendarExtender ID="cal DateOfBirth " Format="dd/MM/yyyy" runat="server" TodaysDateFormat="dd, MM, yyyy" TargetControlID="txtDateOfBirth" Enabled="True"></AjaxControlToolkit:CalendarExtender> 3. Use Ajax Watermark Extender to get the date e.g. <AjaxControlToolkit:TextBoxWatermarkExtender ID="TextBoxWatermarkExtender3" runat="server" TargetControlID="txtDateOf...