How To Display Watermark In ASPX Textbox Using AJAX Control Toolkit In ASP.NET With C#

In this post, we will learn how to add a watermark inside textbox using AJAX Control Toolkit using C#. For this example first, we have to install the AJAX Control Toolkit from the NuGet package. For this example, we have to add ScriptManager, aspx TextBox, and TextBoxWatermarkExtender for displaying the watermark text in the textbox. Let's start coding.

source https://www.c-sharpcorner.com/Blogs/how-to-display-watermark-in-aspx-textbox-using-the-ajax-control-toolkit-using-asp-net-with-c-sharp