note 50104 added to function.setcookie

I have a login form, when a user logged in and after being verified, I used the setcookie to store the value of the username and password to a cookie. When the user log out, I also used the setcookie clear the user information in that cookie using the setcookie function again. But then, even if I set the value to "", and try to print the the value of the cookie, i found out that the value of the cookie is still there. How come this happens? ---- Manual Page -- http://www.php.net/manual/en/function.setcookie.php Edit -- http://master.php.net/manage/user-notes.php?action=edit+50104 Delete: added to the manual -- http://master.php.net/manage/user-notes.php?action=delete+50104&report=yes&reason=added+to+the+manual Delete: bad code -- http://master.php.net/manage/user-notes.php?action=delete+50104&report=yes&reason=bad+code Delete: spam -- http://master.php.net/manage/user-notes.php?action=delete+50104&report=yes&reason=spam Delete: useless -- http://master.php.net/manage/user-notes.php?action=delete+50104&report=yes&reason=useless Delete: other reasons -- http://master.php.net/manage/user-notes.php?action=delete+50104&report=yes Reject -- http://master.php.net/manage/user-notes.php?action=reject+50104&report=yes Search -- http://master.php.net/manage/user-notes.php