Introduction

Welcome to the world of Hypertext Preprocessor (PHP). PHP is a popular programming language that's used all over the internet to create web pages/websites and applications. A web page is a single page, while multiple web pages together are commonly referred to as a website or web application. PHP powers sites such as Facebook, Wikipedia, and WordPress.

PHP was created as a scripting language to allow rich dynamic content (content can come from other PHP pages or can be dynamic in nature and come from external sources such as a database). PHP is an interpreted language, which means you do not have to compile it and create an executable file. Instead, PHP files are interpreted line by line by the web server running PHP.

Compiled languages cannot run directly after each change. Instead, they require an interpreter to compile the code into a program that can be executed. Interpreted languages, on the other hand, can be reloaded as soon as there is a change in the code, allowing for changes to be seen quickly.

PHP is used along with HTML, JavaScript, and CSS to create dynamic web applications. Since PHP is easy to learn, it has a huge developer community around the world. This has led to more and more developers releasing open source projects, frameworks, and resources. For instance, PHP Framework Interop Group, otherwise known as PHP-FIG, (https://packt.live/2oJ0FvY) has created a series of standard recommendations that most developers use to write their code. GitHub houses many open source projects for others to use, and sites such as https://packt.live/2oaK3gt have many videos on web development.