HTTP is a stateless protocol, actually statelessness is one of the many advantages of the World Wide Web. In a statelessness condition all information associated with the page and the controls on the page would be lost with each round trip . Round trip means a request from a user to Web Server and response from Webserver to user . There is no standard way in which the server can determine whether a subsequent HTTP request is from the same user.
To overcome this limitation of traditional Web programming, ASP.NET includes several features that help you preserve data on both a per-page basis and an application-wide basis by its State Management Capabilities. ASP.NET provides various options for state management such as Client-Based State Management Options and Server-Based State Management Options.
Client Based State Management Control State Hidden Fields Cookies
Server Based State Management application state session state
Each option has distinct advantages and disadvantages, depending on the scenario. From the following chapters you can see some important state management features in detail.