One cool feature of the HTML5 specification control is the placeholder attribute. Currently you won’t see any support for ASP.NET Webform textbox control.
This article will let you create a custom control to do that.
Creating an ASP.NET Web Control is easy, all you need to do is toÂ makeÂ sure that the textbox supports placeholder attribute. Then create a new ASP.NET Server Control using MS Visual Studio and select C# as the language.
After that, modify the placeholder public control, then modify your custom control.
Read the rest of the tutorial here:Â http://dotnet.dzone.com/articles/html5-placeholder-support