MySQL Cookbook

Creating Forms in Scripts

Problem

You want to write a script that gathers input from a user.

Solution

Create a fill-in form from within your script and send it to the user. The script can arrange to have itself invoked again to process the form’s contents when the user submits it.

Discussion

Web forms are a convenient way to allow your visitors to submit information, for example, to provide search keywords, a completed survey result, or a response to a questionnaire. Forms are also beneficial for you as a developer because they provide a structured way to associate data values with names by which to refer to them.

A form begins and ends with <form> and </form> tags. Between those tags, you can place other HTML constructs, including special elements that become input fields in the page that the browser displays. The <form> tag that begins a form should include two attributes, action and method. The action attribute tells the browser what to do with the form when the user submits it. This will be the URL of the script that should be invoked to process the form’s contents. The method attribute indicates to the browser what kind of HTTP request it should use to submit the form. The value will be either GET or POST, depending on the type of request you want the form submission to generate. The difference between these two request methods is discussed in Recipe 18.6; for now, we’ll always use POST.

Most of the form-based web scripts shown in this chapter share some common behaviors:

• When ...