A user’s interaction with an application is called a session. A session can encompass several page requests. For example in an e-commerce application, a session can involve browsing the products for sale, adding some of them to a shopping cart, entering payment and shipping information, and finalizing the transaction.
During a session, the user assigns values to page items, perhaps over several pages, and sends these values to the server for processing. The item values for a given session comprise what is called its session state. In this chapter you will examine the various ways that an application can modify and access ...