The main way that website users interact with PHP and MySQL is through the use of HTML forms. These were introduced very early on in the development of the World Wide Web—in 1993, even before the advent of ecommerce—and have remained a mainstay ever since, due to their simplicity and ease of use.
Of course, enhancements have been made over the years to add extra functionality to HTML form handling; this chapter will bring you up to speed on the state of the art and show you the best ways to implement forms for good usability and security.