PHP is a popular, general purpose, agile scripting language. It’s open-source, and created with web development – particularly server-side scripting – in mind. It was actually one of the fundamental technologies in the development of many internet giants like Facebook, WordPress or Wikipedia.
It simplifies server-side development, and it’s one of the most widely used languages. The main difference between the same application written in PHP and, say, JavaScript, is that PHP executes code on the server, and only sends HTML files to the client. The client doesn’t see underlying server-side code responsible for generating those files.
Apart from server-side scripting, PHP can be used for command line scripting to build tools that automate tasks like simple text processing. PHP can also be used to build desktop applications with the PHP-GTK extension.
PHP supports the majority of web servers, like Nginx IIS and Apache, as well as all the most important operating systems, including Windows, OS X, Linux, and different Unix variations. It allows developers to use an object-oriented programming approach, a procedural approach, or a combination of both.
It can output HTML, images, PDFs, Flash movies generated in real time, text as XHTML and any XML file. PHP can be used to build a server-side cache for dynamic content.
This programming language also has support for all of the most relevant databases, with database-specific extensions. It can be hosted virtually anywhere, it’s platform-independent, and it is easy to scale.
PHP is safe for the server, because toxic requests can’t bring the whole server down, and request errors don’t affect it much.