The Internet and the World Wide Web
The Internet comprises a vast number of computers, network links between the computers, and protocol and other interface standards that provide a communication network for computer representatives to exchange computer data with other computer representatives. The World Wide Web ("WWW") was designed as an easy visual interface for representatives of the Internet. The WWW allows a server computer, called a Web site, to send graphical Web pages of information, called Web pages, to a remote representative's computer and allows the remote representative's computer to display the Web pages on a display. These Web pages may contain control regions, such as simulated push buttons, that allow the representative to acquire and display additional, related Web pages of information in a hypertext fashion.
The Internet is based on information exchange from servers to clients. Each client and server has an Internet address called a Uniform Resource Locator ("URL"). An example of a URL address is "http://acme.com/page1." The URL has two parts: (1) a scheme and (2) a scheme-specific part. The scheme identifies the high-level protocol through which the information is to be exchanged, and the scheme-specific part contains additional information useful in establishing a connection between a client and a server. The WWW uses the HTTP protocol. The "http" at the beginning of the example URL, above, is the scheme, and indicates that the Internet address specified by the example URL exchanges information using HTTP, and is therefore a WWW site. The remainder of the URL following the colon is the scheme-specific part that, for WWW servers, generally indicates a host HTTP server name and the file system path to a Web page to be transferred. In this example, the host HTTP server is identified by "acme.com" and the Web page is identified by "page1."
Currently, a Web page is defined by a HyperText Markup Language ("HTML") file. The software on a client that manages the Internet connections and interprets and effects the commands contained in HTML documents is called a browser. When a representative indicates to the browser a desire to view a Web page, the browser initiates a client computer request that the server transfer to the client computer an HTML file that defines the Web page. When the requested HTML file is received by the client computer, the browser uses the HTML file to construct the Web page and display it to the representative on the client computer display. The HTML file contains various commands for displaying text, graphics, controls, background colors for the Web page, and other displayed features. The HTML file may contain URL addresses of other Web pages available on the server, which allow the browser to offer to the representative hypertext-type selection and display of the other Web pages. In addition, the HTML file also may contain URL addresses, called hot links, to other Web pages at other Web sites. Thus, a representative may be able not only to navigate among Web pages available on the server to which he initially connected, but also among Web pages on entirely different servers. Additional types of Web page description facilities, other than HTML, are either currently available or planned for future release.
In general, the Web servers are stateless with respect to client transactions. In other words, at the HTTP protocol level, each transaction (e.g., request for an HTML file) is separate from all others. In other common networking system protocols, a client might initialize a connection to the server, conduct a series of requests from the server and receive information for each request, and then terminate the connection from the server, and the entire exchange, from the initialization to the termination of the connection, would be considered a transaction. In such systems, the client/server connection may be considered to be in one of several different states at any instance, depending on the nature of the requests and responses and their order. Such systems require that state information be saved by the server, and also usually by the client, and require time outs and other connection failure strategies. The stateless nature of the Web simplifies the server and client architectures.