PHP, which stands for "PHP: Hypertext Preprocessor", is an HTML-embedded scripting language. Much of its syntax is borrowed from C, Java and Perl with some unique features thrown in. The goal of the language is to allow web developers to write dynamically generated pages quickly.
Note, that PHP is not only a Hypertext Preprocessor today. You can generate images, PDF files or even Flash animations on the fly with simple PHP scripts. Also check PHP-GTK to see, that PHP can be used to write client-side GUI applications.
This manual is written in XML using the DocBook XML DTD, using DSSSL (Document Style and Semantics Specification Language) for formatting. The tools used for formatting HTML and TeX versions are Jade, written by James Clark and The Modular DocBook Stylesheets written by Norman Walsh. We use Microsoft HTML Help Workshop to generate the WinHelp format of the manual.
You can download the actual manual in various languages and formats, including plain text, plain HTML, PDF, PalmPilot DOC, PalmPilot iSilo and WinHelp, from http://www.php.net/docs.php. The manuals are updated daily.
You can find more information about downloading the XML source code of this documentation at http://cvs.php.net/. The documentation is stored in the phpdoc module.