session problem

Hi list, I've made this script in order to solve the problem with reload button that I've posted. My idea is to register in a session the id, them check if it exists, if so don't insert again. But even if I quit the browser the session persists. Why?? ps: this is an include in the main page where I use session_start(); if(!$visita) { $visita = array(); } if(!in_array($celebID,$visita)) { $sql_log = "INSERT INTO log_hits (logID,log_date,log_ip,log_referrer,log_celeb,log_url) VALUES('',now(),'$REMOTE_ADDR','$HTTP_REFERER','$celebID','$REQUEST_URI')"; $query_log = new Query($conexao); $query_log->executa($sql_log); array_push($visita,$celebID); session_register('visita'); } Thank's Rodrigo --