PHP is an open source general-purpose server-side scripting language originally designed for Web development to produce dynamic Web pages. It is one of the first developed server-side scripting languages to be embedded into an HTML source document rather than calling an external file to process data. The code is interpreted by a Web server with a PHP processor module which generates the resulting Web page. It also has evolved to include a command-line interface capability and can be used in standalone graphical applications.
PHP can be deployed on most Web servers and also as a standalone shell on almost every operating system and platform, free of charge. PHP is installed on more than 20 million Web sites and 1 million Web servers.Software that uses PHP includes Drupal, Joomla, MediaWiki, and WordPress.
PHP interpreters are available on both 32-bit and 64-bit operating systems, but on Microsoft Windows the only official distribution is a 32-bit implementation, requiring Windows 32-bit compatibility mode while using Internet Information Services (IIS) on a 64-bit Windows platform. Experimental 64-bit versions of PHP 5.3.0 were briefly available for MS Windows, but have since been removed.
PHP is a general-purpose scripting language that is especially suited to server-side web development where PHP generally runs on a web server. Any PHP code in a requested file is executed by the PHP runtime, usually to create dynamic web page content or dynamic images used on Web sites or elsewhere.
It can also be used for command-line scripting and client-side graphical user interface (GUI) applications. PHP can be deployed on most Web servers, many operating systems and platforms, and can be used with many relational database management systems (RDBMS). It is available free of charge, and the PHP Group provides the complete source code for users to build, customize and extend for their own use.
Originally designed to create dynamic Web pages, PHP now focuses mainly on server-side scripting, and it is similar to other server-side scripting languages that provide dynamic content from a Web server to a client, such as Microsoft’s ASP.NET, Sun Microsystems’ JavaServer Pages, and mod_perl. PHP has also attracted the development of many frameworks that provide building blocks and a design structure to promote rapid application development (RAD). Some of these include CakePHP, Symfony, CodeIgniter, Yii Framework, and Zend Framework, offering features similar to other web application frameworks.