A Brief Overview on How PHP Works
PHP is called hypertext preprocessor. It is a kind of server side scripting language which is deployed in the main web server by the help of some software. This is used to make dynamic web pages. This is the only scripting language which can be used alongside HTML internally. There is no such external process which runs while it is running in the website. There are around 20 million websites which run this one and around 1 million servers which uses it. This was developed by Rasmus Lerdorf, Andi Guttmann and Zeev Surakshi. They released the first version on June 8, 1995. Several other versions were such as PHP2 and PHP3 was released on November 1997 and June 1998 respectively. On May 22, 2000 PHP4 was released which was based on Zend engine I. In late years fifth version was developed by using Zend engine II. The fifth version of this supported many other features such as OOP and PDO extension etc. The later version was released on July 13, 2004.
This software is considered as a general-purpose scripting language which is exclusively suited for server-side website development. Any code of this software is executed by the calling the runtime function which resides inside a file. It is particularly used to create dynamic contents on WebPages such as dynamic images, dynamic menu etc. It can also be used as command-line scripting as well as graphical user interface (GUI) applications. The RDBMS (relational data base management system) used in the software and also the software codes of it releases is available free of charge, and anyone can use the code and customize and reuse it as per requirement. This was originally designed so as to create dynamic Web pages but now it focuses mostly on server-side scripting. It provides a good competition to Microsoft's ASP.NET as well as Sun Microsystems' Java Server Pages (JSP). PHP has also been used in developing many frameworks which creates a design structure for rapid application development (RAD). Some examples are CakePHP, Yii Framework, Symphony, Code Igniter, and Zend Framework.
 Till April 2007, more than 20 million Internet domains had Websites which were hosted on enables servers. There are many Web content management systems which were written in PHP such as Media Wiki, Word Press, Drupal, Joomla, eZ Publish, Silver Stripe and Module. Many famous websites such as Wikipedia, Facebook, and Digg are developed using the scripts. As other scripting languages this is also prone to many security threats and vulnerabilities. But in spite of these risks there are web servers which implement the software in their network as it is one of the best dynamic webpage making tool.
