Introduction to PHP

PHP is a scripting language that is used primarily to develop dynamic web pages. PHP scripts are executed directly on the server and not in the browser of a visitor.

PHP was developed in 1995 by RasmusLerdorf. His goal was to create a simple replacement for the collection of use-ful Perl scripts. This is how Personal Home Page Tools came into being. Soon after, he recreated the tool collection in the programming language C.

Today, PHP is still developed in C, a very powerful programming language. It was soon followed by the first version, PHP / FI (Form Interpreter).

In 1998, Andi Gutmans and ZeevSuraski, in cooperation with Lerdorf, created PHP 3 from scratch to make it ready for use, particularly in the booming e-commerce business. Gutmans and Suraski founded the company Zend Technol-ogies Ltd., which contributed the main parts of PHP 4.

In 2004, PHP5 introduced enhanced support for object-oriented programming and greatly increased the speed of the PHP interpreter.

Eleven years later, in 2015, PHP 7 was released. It is powered by a new engine with a fast speed. PHP 6 was skipped because projects planned to carry out the program were never finished and so the developers focused on a completely new core engine. Most scripts execute twice as fast as in PHP 5.x. The majority of old PHP 5 scripts only need small changes to run in PHP 7. Scripts in this book are all updated to be fully compatible.

Common Uses of PHP:

PHP performs system functions, i.e. from files on a system it can create, open, read, write,and close them.

PHP can handle forms, i.e. gather data from files, save data to a file, thru emailyou can send data, return data to the user.

You can add, delete, modify elements within your database thru PHP.

Access cookies variables and set cookies.

Using PHP, you can restrict users to access some pages of your website.

You can send emails to the users of your website.