Fall Semester 2007
Here's a simple program to start from.
The program uses hidden fields (just one, in this case) to keep state.
Here's the same program converted to server-side state.
As can be seen the program uses PHP sessions.
Server-side state has obvious advantages but also one disadvantage.
Here's how we disable accidental reloads: program.
As can be seen two things need to be on the client side: the user id and the transaction id (age).