What is PHP?
PHP is a Programming Language used to creating dynamic web sites. PHP is much faster than Java and is easy to learn.
Introduction to PHP
Arrays in PHP
Multi Dimensional Arrays
Functions in PHP
Functions with parameters
Function returning values
PHP Code Optimization Tips
What can PHP do?
Anything what you want it to do. PHP is mainly focused on server-side scripting.
This is the most traditional and main target field for PHP. You need three things to make this work. A webserver and a web browser. You need to run the webserver, with a connected PHP installation. You can access the PHP program output with a web browser, viewing the PHP page through the server.
Command line scripting
You can make a PHP script to run it without any server or browser. You only need the PHP parser to use it this way. This type of usage is ideal for scripts regularly executed using cron (on *nix or Linux) or Task Scheduler (on Windows). These scripts can also be used for simple text processing tasks.
Writing client-side GUI applications
PHP is probably not the very best language to write windowing applications, but if you know PHP very well, and would like to use some advanced PHP features in your client-side applications you can also use PHP-GTK to write such programs. You also have the ability to write cross-platform applications this way.