copy code,drag or close
This button comes from a database, it is simple HTML stored in a record.
It could be a .NET control which, when clicked would produce some server side processing based on what ever code the event handler would call.
The .NET server control can also be stored in a database if required; to get it to run as you would expect a normal control to run if you add it to a page you need to surround it within a .NET literal control.
A Web service can return any type of complex object if needed such as a user defined object, simple text or, if you wanted a button.
And of course that button could be stored in a database.