Introduction

To make your site interesting, informative and interactive you will need to do more than simply link the pages together with hyperlink. For example, you might provide a search engine to allow a user to find information in documents on the server. If you are promoting multimedia applications, you might want to start a multimedia server from a Web page. This chapter describes how to enhance your Web pages by writing programs and scripts that run as complex applications on the server or to enhance the functionality of basic HTML commands.

I cover a wide range of programming techniques within this chapter, from the latest JavaScript and VBScript methods through to the traditional (if such a term can apply to the Internet) such as Perl. I have included guidelines and program examples and show you how to create a range of effects from multimedia effects to a search engine.

The system that ties all these technologies together is called CGI (common gateway interface) and it provides the method of controlling and passing information to programs running on the server from a Web page. Since CGI is crucial to understanding how to create applications and tells you how the programs are used, I start with a brief description of CGI and the HTTP conversations between a browser and server.

Accessing information: CGI and the HTTP server

When a form has been completed by a user, the information it contains is sent by the browser to the HTTP Web server defined...