设置cookie有关问题

设置COOKIE问题
if(isset($_COOKIE['history']))
{
$history = explode(',', $_COOKIE['history']);

     array_unshift($history, $id);
     $history = array_unique($history);

     while (count($history) > 5)
     {
         array_pop($history);
     }

setCOOKIE('history',implode(',', $history),80000);
echo 'add';
}
else
{
setCOOKIE('history',$id,80000);
echo 'new';
}


为什么一直都是输出new呢