The current chapter PHP Introduction gives the clear information of PHP Uses and how it works. PHP is an open source general purpose scripting language, that has the full form of "Hypertext Preprocessor". PHP is a server side scripting language. PHP scripts will run and interact with the servers and gives the HTML output. PHP is a language that is used for web development by web developers.Originally PHP was known as "Personal Home Page Tools". Later on after PHP version 3 it is being known as PHP Hypertext Preprocessor. PHP is used on millions of servers world wide. Now a days, PHP is a very powerful language, which is widely used for CMS(like wordpress, Joomla, Drupal) and it is being used in many frameworks. For example, Zend framework, Cake frame work, etc. PHP plays main role in E-commerce Sites and in the social networking sites also.

• PHP permits the web developers to build content dynamically which communicates with the databases.
• PHP is mainly helps in developing web based software applications.
• User Login authentication, i.e. Validation can be done on the server side and can control the user access permissions.
• PHP can deal with forms, i.e gather information from files, save information to a file, email the data can be sent and return data to the end user.
• Encryption and decryption of the data can be done.
• The elements can be added, deleted and modified within the database through PHP Cookie variables can be accessed and set.
• PHP performs system functions, i.e. from files on a system it can create, open, read, write and close them.
• Parsing XML Files.
• Own Mailing Scripts can also be written using PHP.

• PHP is free, open source scripting language and can download it freely from PHP official site.
• PHP is compatible with most of the services(Apache, IIS)
• The scripting validation will be done on server side.
• PHP is not tag based and is fast and stable.
• It can be run in various platforms( like Windows, Mac, Unix, Linux, etc.,), so it is called as platform independent.

Suppose there is a potential user who is browsing through the web and comes across a website page that ends with the extension .php. Then a client web browser request is then initiated to the web server where the entire website is located including the PHP files. The web server directs the request to the PHP interpreter and runs the PHP files and generate a new page file which has an extension .php by communicating with the databases, file systems and email servers. But this new file comes to the client as HTML. All the PHP scripting process is done on the web server. The final product that comes in is the HTML. Thus PHP gives life to HTML.

The chapter PHP Introduction draws out the following main points.

• PHP is Hypertext Preprocessor.
• PHP allows to build web pages dynamically that communicates with the databases.
• PHP sends the requests to web servers which manipulates the .php pages to give the output in the form of HTML.