PHP (disambiguation).

PHP

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This article is about the scripting language. For other uses, see PHP (disambiguation).

PHP

PHP: Hypertext Preprocessor
Paradigm(s)	imperative, object-oriented, procedural, reflective
Appeared in	1995; 17 years ago[1]
Designed by	Rasmus Lerdorf
Developer	The PHP Group
Stable release	5.4.9 (November 22, 2012; 21 days ago)
Typing discipline	Dynamic, weak
Major implementations	Zend Engine, Phalanger, Quercus, Project Zero, HipHop
Influenced by	Perl, C, C++, Java, Tcl[1]
Implementation language	C
OS	Cross-platform
License	PHP License
Usual filename extensions	Common extensions .php Older, now uncommon extensions .phtml, .php4 .php3, .php5, .phps
Website	www.php.net
PHP Programming at Wikibooks

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.^[2] PHP can be deployed on most Web servers and also as a standalone shell on almost every operating system and platform, free of charge.^[3] A competitor to Microsoft's Active Server Pages (ASP) server-side script engine^[4] and similar languages, PHP is installed on more than 20 million Web sites and 1 million Web servers.^[5] Software that uses PHP includes Drupal, Joomla, MediaWiki, and WordPress.
PHP was originally created by Rasmus Lerdorf in 1995. The main implementation of PHP is now produced by The PHP Group and serves as the formal reference to the PHP language.^[6] PHP is free software released under the PHP License, which is incompatible with the GNU General Public License (GPL) due to restrictions on the usage of the term PHP.^[7]
While PHP originally stood for Personal Home Page, it is now said to stand for PHP: Hypertext Preprocessor, a recursive acronym.^[8]

Contents

• 1 History
  • 1.1 Licensing
  • 1.2 Release history
• 2 Usage
• 3 Security
• 4 Syntax
  • 4.1 Data types
  • 4.2 Functions
    • 4.2.1 PHP 5.2 and earlier
    • 4.2.2 PHP 5.3 and newer
  • 4.3 Objects
    • 4.3.1 Visibility of properties and methods
• 5 Speed optimization
• 6 Compilers
• 7 Resources
• 8 See also
• 9 Notes
• 10 External links