Simple $_GET example for Leo

<?php
    // First we get the variable we want to look at from the $_GET array
    $page = $_GET['p'];
    
    // We should never trust the user's input to be safe
    // So let's restrict the possibilities with a switch() statement
    // If the input is invalid, we return some sort of error
    switch($page) {
        case 'home':
            // show the home page text
            break;
        case 'about':
            // show the about page text
            break;
        case 'contact':
            // show the contact page text
            break;
        default:
            // none of the above
            // show an error
            die('Invalid page!');
            break;
    }