Maintaining state

Sometimes you want to have an extended dialog with the user. Say he or she provides some input, and based on that input you want to ask some more questions. This can be troublesome over the web because HTTP is a stateless protocol. That is, each contact between the browser and the server is unique--there's no history (state).

There are several ways around this, and most involve sending state information back to the user in a way that it is re-sent to the server in the next communication.

For example, consider this multi-stage process:

User requests data in a certain time range
Server checks that the time range makes sense
Server reports back to the user about the time range and, if it is OK, asks for more input
User provides more input
Server processes the final request

Last modified: Wed May 15 16:11:10 DST 1996