HTML and CSS Reference
customer name, his or her e-mail address, and the receipt number of the order so that
the restaurant can match up each survey response with a specific customer order.
Forms and Server-Based Programs
Before you start work on the survey form, you should understand how such data is pro-
cessed on the Web. As shown in Figure 6-3, a Web form is used to collect information,
but the data itself is usually stored and analyzed by a program running on a Web server.
interaction between a web form and a web server
data from the Web form is
sent to a program running on
the Web server
feedback from the Web server
can be sent back to the client
A form designer might not have permission to create or edit programs that run on Web
servers. Instead, the designer usually receives instructions about how to interact with the
server programs; these instructions usually include a list of fields that are required by a
program and a description of the types of values expected in those fields.
There are several reasons to restrict direct access to these programs. The primary reason
is that when you run a server-based program, you are interacting directly with the server
environment. Mindful of the security risks that computer hackers present and the drain on
system resources caused by large numbers of programs running simultaneously, system
administrators are understandably careful to maintain strict control over their servers and
systems. Otherwise, people could use malicious code to inject programming into the
server and possibly change the prices of items or degrade the performance of the server.
Server-based programs are written in a variety of languages. The earliest and most
common of these programs are Common Gateway Interface (CGI) scripts, written in a
language called Perl. Other popular languages widely used today for writing server-based
programs include the following: