PHP is free of charge and easy to use. Its creator, Rasmus Lerdof, started with a script to log visitors interested in his online resume! But soon the developer community started believing in this language. Today, it may be used on around 100 000 sites all over the world!

This PHP reference introduces a hundred key functions used in the 4.0 version of the language. A concrete example has been assigned to each function. To use them, simply insert the described code in an HTML page, making sure you enclose it between the <? and ?> tags, or the <?php and ?> tags. Once the file has been placed on the server, the PHP code will automatically be interpreted when it is called up.

The main PHP functions classified in categories:

• Input/output functions;
• General data handling functions;
• Array handling functions;
• String handling functions;
• Conversion functions;
• Regular expressions;
• Date and time functions;
• Calendar functions;
• Configuration functions.



• All PHP 4.0 functions.