When you create a form that is a design element, a user interface, the
"front-end" as it's called. A form is just a conduit for data, the user
enters the data and the form sends the data to the server and the server
processes the data. When you use a form "control" in Publisher it writes the
programming logic behind it and that is run by FrontPage Server Extensions
software on the server, that programming code being run on the server to
process the data in the form is the "back-end". If you need advanced
handling of data such as calculations then you need to get into programming.
On the Windows platform you would use ASP.Net for your web programming.
Visit http://www.asp.net

David Bartosik - [MSFT MVP]
http://www.publishermvps.com
http://www.davidbartosik.com