Postcode check (Opgelost)

<?php
(!preg_match('~^[1-9][0-9]{3}[a-z]{2}$~i', $_POST['Postcode'])
?>

<?php
(!preg_match('~^[1-9][0-9]{3}[a-z]{2}$~i', $_POST['Postcode'])
?>

preg_match('~^[1-9][0-9]{3}[[:blank:]]?[a-z]{2}$~i', $_POST['Postcode']);

preg_match('~^[1-9][0-9]{3}[[:blank:]]?[a-z]{2}$~i', $_POST['Postcode']);