You've installed PHP and the other software components necessary to begin using PHP5, and you know that the majority of your programs will be designed to run from a Web server, using HTML-or XHTML-based Web pages for displaying the user interface and results of data processing in a browser (most likely Internet Explorer for PC users).
What you learn in this chapter is the basis for all your PHP programs that run via a browser-based interface. You'll explore the basic aspects of properly writing a PHP program, interspersing your PHP code within the HTML or XHTML of a Web page, the use of several common PHP functions (such as echo, date (), strlen (), and so on), and creating and using variables. You'll develop several simple programs demonstrating typical PHP5 usage with plain Web pages, and get a short recap of how PHP programs run.
You'll learn about operators and expressions, and briefly examine uniquely useful variables called arrays. Arrays are used for data storage like ordinary variables, but have features that make them quite powerful for many types of data processing.
This chapter provides the foundation for the bulk of the material in later chapters because almost all the data processing you'll do in PHP programs depends directly on your ability to properly name and use variables and PHP's type-related functions, and especially arrays.
