What is PHP?
PHP is a programming language that can do all sorts of things: evaluate form data sent from a browser, build custom web content to serve the browser, talk to a database, and even send and receive cookies (little packets of data that your browser uses to remember things, like if you’re logged in to a website).
It’s an interpreted language, which means it gets run by, and interpreted by, a server (usually Apache web server or one of it’s alternatives).
What are variables? Variables are
Arrays are variables that contain multiple pairs of values.
Functions are functional
4. Using PHP
5. Interacting with a MySQL database