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www.it-ebooks.infoC H A P T E R 1• • •Introducing PHPIn many ways the PHP language is representative of the stereotypical open source project, created tomeet a developer’s otherwise unmet needs and refined over time to meet the needs of its growingcommunity. As a budding PHP developer, it’s important you possess some insight into how the languagehas progressed, because it will help you to understand the language’s strengths as well as the reasoningbehind its occasional idiosyncrasies.Additionally, because the language is so popular, having some understanding of the differencesbetween the versions—most notably versions 4, 5, and 6—will help when evaluating Web hostingproviders and PHP-driven applications for your own needs.To help you get up to speed quickly in this regard, this chapter will cover PHP’s features andversion-specific differences. By the conclusion of this chapter, you’ll have learned the following:• How a Canadian developer’s Web page traffic counter spawned one of the world’smost popular programming languages.• What PHP’s developers did to reinvent the language, making version 5 the bestversion yet.• How PHP 5.3 is going to further propel PHP’s adoption in the enterprise.• Which features of PHP attract both new and expert programmers.• Caution A great deal of confusion has arisen from the PHP development team’s perhaps overly ambitiousdecision to work on PHP 6 alongside PHP 5, with the former intended to add Unicode support and the latter addingseveral key features such as namespaces. In March 2010, the team decided to primarily focus on advancing PHP5, placing much less emphasis on a forthcoming version 6. While I’ve no doubt version 6 will eventually bereleased, at the time of this writing you should devote your efforts to building websites which work best with the5.X series.HistoryThe origins of PHP date back to 1995 when an independent software development contractor namedRasmus Lerdorf developed a Perl/CGI script that enabled him to know how many visitors were readinghis online résumé. His script performed two tasks: logging visitor information, and displaying the countof visitors to the web page. Because the Web at the time was still a fledgling technology, tools such as1