June 2000
Intermediate to advanced
470 pages
14h 14m
English
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Chapter 4. Forms and CGI
HTML forms are the user interface that provides input to your CGI scripts. They are primarily used for two purposes: collecting data and accepting commands. Examples of data you collect may include registration information, payment information, and online surveys. You may also collect commands via forms, such as using menus, checkboxes, lists, and buttons to control various aspects of your application. In many cases, your forms will include elements for both: collecting data as well as application control.
A great advantage of HTML forms is that you can use them to create a frontend for numerous gateways (such as databases or other information servers) that can be accessed by any client without worrying about platform dependency.
In order to process data from an HTML form, the browser must send the data via an HTTP request. A CGI script cannot check user input on the client side; the user must press the submit button and the input can only be validated once it has travelled to the server. JavaScript, on the other hand, can perform actions in the browser. It can be used in conjunction with CGI scripts to provide a more responsive user interface. We will see how to do this in Chapter 7.
This chapter covers:
How form data is sent to the server
How to use HTML tags for writing forms
How CGI scripts decode the form data
Sending Data to the Server
In the last couple of chapters, we have referred to the options that a browser can include with an HTTP request. In the ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.