One additional technique for HTTP interaction is the client-side cookies. These are name/value pairs stored on the client and meant to persist between HTTP requests. The server can push cookies down to the client and then check their values on a later request. Cookies are typically used to maintain session information.
A server application will set a cookie using the set-cookie header. An example use might be:
set-cookie: username=jsmith; expires=Tuesday, 04-Jun-2002 00:00:00 GMT; path=/MembersOnly; domain=www.voicexml.org
This causes the client to store a cookie named username with a value jsmith. Each time a cookie-compliant HTTP client makes an HTTP request, it will check the URL to see if it begins with http://www.voicexml.org/MembersOnly ...