Learning PHP & MySQL, 2nd Edition

Chapter 10. Working with Forms

HTML forms provide a way to send substantial data from the user to the server where it can be processed. You’ll be using a lot of the PHP language concepts that you learned about in the first half of the book to process and validate the form data.

We’ll begin by building a simple form and learning how to access the information in its fields after a user’s submission. We’ll discuss the basic types of input devices that can be placed on forms, as well as on hidden values. Of course, the PHP code will be mixed in with all of these elements.

Forms work in a two-step process. The form must be presented to the user. He then enters information and submits the form. Every form has a target for what page to load that will process the data when the user submits. Often, this is the same file that originally generated the form. The PHP code simply checks to see whether there’s user input coming along with the request for the page to determine whether the file is being called to generate the form or process its data.

Searching a database is necessary in many different types of applications. Whether it’s searching forum posts, users, or a blog, it can make a user’s life much easier. On a database level, there are also many different ways to process a search and bring back results.

Building a Form

Since you’ll need a place for the user to enter a search query, let’s begin by building a form to handle the user’s input. Every form must have these basic components:

• The submission ...