PHP+MYSQL+COOKIE5

<?php
header("content-type:text/html;charset='utf-8'");
setcookie('username','',time()-1);
setcookie('islogin','',time()-1);
setcookie('autologin','',time()-1);
exit(
"<script>
alert('退出成功');
location.href='dl.php';
</script>"
);
?>

这句话代表退出了，就-1就行了