Forms lie at the very heart of working with PHP. You use forms for logging in to restricted pages, registering new users, placing orders with online stores, entering and updating information in a database, sending feedback … and the list goes on. The same principles lie behind all these uses, so the knowledge you gain from this chapter will have practical value in most PHP applications. To demonstrate how to process information from a form, I’m going to show you how to gather feedback from visitors to your site and send it to your mailbox.
Unfortunately, user input can expose your site to malicious attacks. ...
