Disable some Button in all Pages using Master Page in ASP.Net

thanks dharmendra sir,

But my i think you have not understand exactly what i want.

my question is that i have multiple pages in a application and there is many buttons in all pages.i want to disable some buttons in all pages using a common code but from the server side not css or javascript.

suppose a user logged in and i want that particular user should not be able to delete some data in whole appliation so how can i implement this .

My application is ready but now this scenario came from the client to do this .so i cant create any role for that particular user.

using some condtions i have to do it but on application level.not a single page.