coockie expiration problems

Hi there, I am trying to save a var inside a cookie for a certain time (in this example 10s): setcookie('referrer', $user_id, time()+10); //expires in one hour Now I would like to get the value, but only if the coockie is valid (if cockie not older than 10 s in this example) echo 'referrer: '.$_COOKIE[referrer]; Unfortunatelly this does not work, the cockie value is always valid, even after expiration time. What am I doing wrong? Thanx for any help on that, Andy