Write a PHP script that calculates the factorial of a given number.

<?php
function calculateFactorial($n) {
    if ($n == 0 || $n == 1) {
        return 1;
    }

    return $n * calculateFactorial($n - 1);
}

$number = 5;
$factorial = calculateFactorial($number);

echo "Factorial of $number is: $factorial";
?>

• The script defines a recursive function calculateFactorial to compute the factorial of a given number.
• The base case checks if the number is 0 or 1, in which case the factorial is 1.
• The recursive case multiplies the number by the factorial of the number minus 1.
• The script then calls the function with a sample number ($number) and prints the result.