A: In the development of Web applications, we often need to be able to do data sharing or passing parameters between pages, and a data session may be used in different places, you need a dedicated mechanism to transfer and save data ;
The so-called session, refers to the connection opening and from the server and the client makes a request to the server response to client requests the entire process. Session tracking is continuous monitoring request and receive a response to the server for the same user, since the communication is the HTTP protocol between the client and the server, the HTTP is a stateless protocol itself, can not save the customer information, i.e., a complete response after the connection is disconnected, the next request, need to re-establish the connection, etc. once created but also to determine whether the connection is the same
Users, so the process is relatively monitoring session, the last session tracking is through technology. There are four:
(1) Page behalf of objects and attributes associated with a page
(2) Request behalf of a request associated with the occurrence of the Web client objects and attributes
(3) the session on behalf of a user for a Web client experience related objects and attributes
(4) the Application on behalf of the objects and attributes associated with the entire Web application.