Online time. Roughly calculate the online time. Bug: IP is the same.

/*
CREATE TABLE `db_online` (
`ip` char(20) default NULL,
`time` char(20) NOT NULL default '',
`name` char(200) NOT NULL default 'Guest'
) TYPE=MyISAM
*/
//Rough calculation of online time, bug: If the IP is the same (LAN -> External network), only one person is recorded. But the chance is very small
session_start();
//Timeout time
$out_time=300;//60*5
$uesr_name=$_SESSION['uesr_name'];
$now=time();
$
$ip =$_SERVER["REMOTE_ADDR"];
mysql_connect("localhost","root","");
mysql_select_db("database");
//Delete outdated users.
mysql_query("delete from `$online` where ($now-`time`)>$out_time or `name`='$uesr_name' or `ip`='$ip' ");
if($uesr_name){
mysql_query(" INSERT INTO `$online` (`ip`, `time`, `name`) VALUES ('$ip','$now','$uesr_name') ");
}else{
mysql_query(" INSERT INTO `$online` (`ip `, `time`, `name`) VALUES ('$ip','$now','visitor') ");
}
?>

The above introduces the online time and roughly calculates the online time. The bug: IP is the same, including the online time. I hope it will be helpful to friends who are interested in PHP tutorials.