Web Development and Design Foundations with XHTML, 5th Edition

9.5Server-Side Processing

Your Web browser requests Web pages and their related files from a Web server. The

Web server locates the files and sends them to your Web browser. Then the Web

browser renders the returned files and displays the requested Web pages. Figure 9.25

illustrates the communication between the Web browser and the Web server.

Figure 9.25

The Web browser

(client) works with

the Web server

Sometimes a Web site needs more functionality than static Web pages—possibly a site

search, order form, e-mail list, database display, or other type of interactive, dynamic

processing. This is when server-side processing is needed. Early web servers used a

protocol called Common Gateway Interface(CGI) to provide this functionality. CGI is a

protocol, or standard method, for a Web server to pass a Web page user’s request

(which is typically initiated through the use of a form) to an application program and

to accept information to send to the user. The Web server typically passes the form

information to a small application program that is run by the operating system and

processes the data, and it usually sends back a confirmation Web page or message. Perl

and C are popular programming languages for CGI applications.

Server-side scriptingis a technology in which a server-side script is embedded within a

Web page document saved with a file extension such as .php (PHP), .asp (Active Server

Pages), .cfm (Adobe ColdFusion), .jsp (Sun JavaServer Pages), or .aspx (ASP.Net).

Server-side scripting differs from CGI in that it uses direct execution—the script is run

either by the Web server itself or by an extension module to the Web server.