Learning PHP, MySQL & JavaScript, 4th Edition

Chapter 3. Introduction to PHP

In Chapter 1, I explained that PHP is the language that you use to make the server generate dynamic output—output that is potentially different each time a browser requests a page. In this chapter, you’ll start learning this simple but powerful language; it will be the topic of the following chapters up through Chapter 7.

I encourage you to develop your PHP code in one of the IDEs listed in Chapter 2. It will help you catch typos and speed up learning tremendously in comparison to less feature-rich editors.

Many of these development environments let you run the PHP code and see the output discussed in this chapter. I’ll also show you how to embed the PHP in an HTML file so that you can see what the output looks like in a web page (the way your users will ultimately see it). But that step, as thrilling as it may be at first, isn’t really important at this stage.

In production, your web pages will be a combination of PHP, HTML, and JavaScript, and some MySQL statements laid out using CSS, and possibly utilizing various HTML5 elements. Furthermore, each page can lead to other pages to provide users with ways to click through links and fill out forms. We can avoid all that complexity while learning each language, though. Focus for now on just writing PHP code and making sure that you get the output you expect—or at least that you understand the output you actually get!

Incorporating PHP Within HTML

By default, PHP documents end with the extension