Advanced PHP

• Turn off register_globals. Access variables via $_GET, $_POST, $_COOKIE, etc.

... Dude, its faster! Heh! Hehe!

• Create specific parameters for input data, and make sure they match only that data

<?php
if (!is_numerical($_GET['age']) && 
    $_GET['age'] < 0 || $_GET['age'] > 200) {
    die("Invalid age given");
}
?>