PHP (Hypertext Preprocessor) is a scripting language for developing web applications. It is supported by most hosting providers and is one of the most popular tools for creating dynamic websites (3rd place in Tiobe ranking). Among the sites that use PHP, such famous projects, such as Wikipedia, Vkontakte, Facebook, etc.
Danish programmer Lerdorf in 1994, developed scripts in Perl / CGI, collecting statistics about the visitors to his online resume, and called it a Personal Home Page. When Perl functionality became insufficient, Lerdorf wrote a PHP/FI template interpreter in C. His second version was released in 1997 after much testing.

A year later, Israeli programmers Suraski and Gutmans rewrote the interpreter code and released PHP 3.0. Over the next 6 years, a group of enthusiasts made numerous changes to the language. Today, the latest version is PHP 5.0. PHP 6.0 has been under development since 2006.

Using

PHP scripting language has gained wide popularity due to its speed of processing, simplicity, cross-platform, functionality and distribution of the source code under its own license. A wide set of built-in tools is used to develop and promote websites:

• automatic extraction of server environment variables, GET and POST parameters into predefined arrays;
• interacting with various database management systems (SQLite, MySQL, DBX, Microsoft SQL Server, dBase, DB++, and many others);
• sending HTTP headers in automatic mode (facilitates search engine optimization of the site);
• processing files uploaded to the server;
• work with remote and local files, sessions, sockets, HTTP authorization, cookies, XForms.

When promoting sites also use the power of PHP to create user interfaces and scripts to collect statistics.

Features of

PHP syntax is similar to that of C. Some elements, such as associative arrays, are borrowed from Perl. It is possible to start a program with a PHP statement, variables are not required to be declared.

The language executes code inside the bounding tags . Data outside these tags is rendered in standard HTML document markup. Variable names begin with a $ character and are case-sensitive, like class, function and constant names. Variables are handled in double-quoted or apostrophe strings, as well as those created with the <<< operator.

Scripts are handled by the interpreter in an order that ensures the cross-platform nature of the application.