<?php function countdown($event,$month,$day,$year) { $remain = ceil((mktime(0,0,0,$month,$day,$year) - time()) / 86400); if ($remain > 0) { print "<p><strong>$remain</strong> ngày nữa là đến $event</p>"; } else { print "<p>$event has arrived!</p>"; } } countdown("Christmas Day", 12, 25, 2013); ?>