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).