APPENDIX A

Understanding Web 

A

Applications

A web application is a collection of web pages that interact with visitors, 

with each other, and with various resources on a web server, including 

databases. Before you start building your own web applications, you should 

be familiar with the concepts discussed in this chapter. 

The chapter contains the following topics:

About web applications  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  217

How a web application works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219

Authoring dynamic pages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  224

Choosing a server technology. . . . . . . . . . . . . . . . . . . . . . . . . . . . .  226

Web application terminology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .227

About web applications

A web application is a website that contains pages with partly or entirely 

undetermined content. The final content of a page is determined only 

when the visitor requests a page from the web server. Because the final 

content of the page varies from request to request based on the visitor's 

actions, this kind of page is called a dynamic page.

Web applications are built to address a variety of challenges and problems. 

This section describes common uses for web applications and gives a 

simple example. 

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