PHP introduction and uses

It was initially created by Rasmus Lerdorf in 1994. As of today, the current version of PHP is version 5, with version 6 in the making. it is the most popular scripting language on the web.It was initially called Personal Home page

What is PHP?
PHP stands for PHP Hypertext Preprocessor. PHP is a widely-used, open source scripting language. It is similar in syntax to C, Java and Perl with a couple of unique PHP-specific features thrown in. The goal of the language is to allow web developers to write dynamically generated pages quickly .PHP scripts are executed on the server and return the html or plain text to the browser
PHP features
PHP is a power full language and it can do all the functions like
a) it can create, open, read, write, delete, and close files on the server
b) It can collect form data
c) it can send and receive cookies.It can set session key
d) It can connect to many database like oracle,mysql ,sql server to add, delete, modify data in your database
e) A complete username password system can be built over it to control user-access
d) It can encrypt/decrypt data
e) It has all the if else,loop construct to help generate the dynamic page content
f) It can not only generate output in HTML/text. It can output XHTML and XML.

Why PHP is useful and so famous?

There are various reason why PHP is so famous and used in all web development projects. The largest blogging platform wordpress is built over PHP
1) it runs on various platforms (Windows, Linux, Unix, Mac OS X,Solaris,Exalogic,ibm etc.)
2) it is compatible with almost all servers used today (Apache etc.)
3) it supports a wide range of databases. It can connect to oracle,mysql,sqlserver,sqllite etc
4) it is free. Download it from the official PHP resource: www.php.net
5) PHP learning curve is quite simple and we can use it quite efficiently as a language of website

As of now,  millions Internet domains had web services hosted on servers with PHP installed and mod_php was recorded as the most popular Apache HTTP Server module.
Some more Important terms in relation to php

1) php files have extension of .php
2) They are executed on the server and whatever output it generates is sent to browser.So the server is the brain here, not your browser
3) The php script can have html,java script,jquery
4) PHP is a scripting language, like HTML. That means that code does not need to be compiled before it gets used — it gets processed on the fly as necessary

5) It is similar to .net, asp , mod_perl