An Introduction to PHP

There are a lot of different kinds of programming languages which are used in the process of web design. These include both languages which are interpreted by the user’s web browser, like HTML and CSS, which are the basic infrastructure of most web pages, as well as programming languages which are deployed on the server side, running on the same web servers which host and/or serve web pages to users as they navigate the web.

There are a number of commonly used server side programming languages, with PHP being one of the best known and most widely deployed of these. If you’d like to learn a little more about what PHP is, what it is used for and about the history and development of this important server side scripting language, you’ve come to the right place; keep reading for an introduction to PHP.

PHP is both an acronym and a recursive acronym. It originally stood for « Personal Home Page », but is now more commonly regarded as meaning « PHP: Hypertext Processor », an acronym which is actually far more apt when you consider what PHP is actually used for in the process of web development and web design. What web developers and designers generally use this powerful scripting language for is to create dynamic web pages (like many blogs and other Web 2.0 content) which are more interactive than conventional static HTML-based web pages.

The code is often written right into the HTML/XHTML source of the web page. This embedded code is then interpreted by a PHP processor module installed on the page’s web server, which in turn produces the web page based on the HTML and PHP code and serves it to the user, whose web browser renders the page sent by the server. It’s really not much more complex than that; at least as far as non-programmers are concerned. A PHP parser compiles PHP code input and produces non-PHP code (usually HTML) as output.

PHP was first developed in 1995 and has since become more and more common as a server side scripting language for the web and has gone from something which was known only to a relatively small number of people involved in web design to a tool which is deployed on over a million servers and at least 20 million websites worldwide.

Once people discovered the capabilities of this robust scripting language, it became the scripting tool of choice for creating an interactive user experience on the web. Along with its price tag (free), PHP offers a wide range of capabilities which have led to its rapid adoption and worldwide popularity.

PHP’s flexibility has led to it being used for applications other than server side web development; it is available as a command line application with a variety of uses and is also the language in which some client-side programs have been written, complete with graphical user interfaces. Since it can be run on the vast majority of hardware platforms and is compatible with most operating systems, it is an obvious choice for developers working on cross-platform applications which offers high performance while placing less of a load on hardware resources than do programs written in Java and other languages.

PHP 5 is, at least for the time being, the only stable version of PHP which is under active development. PHP 6 was in the development process, but the implementation of Unicode proved to be more problematic than was expected and the version has been delegated to a separate branch rather than to the stable PHP 5 branch. However, the language is constantly being developed and is evolving right along with the World Wide Web itself and the latest version is mature and stable enough that support for the previous version, PHP 4, has been dropped by many software developers and vendors.

Another use for PHP which has come along recently is LAMP architecture for web based applications. LAMP is an acronym for Linux, Apache, MySQL and PHP (in many cases, though it can also mean the Perl or Python scripting languages in some systems). PHP is also one of the workhorses of Web 2.0, being the language that many content management systems are written in, such as WordPress, Joomla and Drupal to name a few; it is also used in the user-facing side of Wikipedia and Facebook along with many other websites.

With a history of providing a reliable framework for dynamic content and versatile enough to find an array of other uses in web design and on individual PCs, PHP is a scripting language which anyone who develops applications for the web or builds websites needs to become familiar with – and many would say that it is the single most important one to learn.

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