useronline.php ทำยังไงเหรอคับจากโค้ด มีโค้ด useronline.php

<?
include "config.inc.php";
$timeoutseconds = 600;
$timestamp = time();
$timeout = $timestamp-$timeoutseconds;
mysql_connect($host,$user,$passwd);

if ($_SERVER['HTTP_CLIENT_IP']) {
$IP = $_SERVER['HTTP_CLIENT_IP'];
} elseif (ereg("[0-9]",$_SERVER["HTTP_X_FORWARDED_FOR"] )) {
$IP = $_SERVER["HTTP_X_FORWARDED_FOR"];
} else {
$IP = $_SERVER["REMOTE_ADDR"];
}

$o_sql = "INSERT INTO webboard_useronline (timestamp,ip,file) VALUES ('$timestamp','$IP','$PHP_SELF')";
$o_result = mysql_db_query($dbname,$o_sql);

$o_sql1 = "DELETE FROM webboard_useronline WHERE timestamp < $timeout";
$o_result1 = mysql_db_query($dbname,$o_sql1);

$o_sql2 = "SELECT DISTINCT ip FROM webboard_useronline WHERE file = '$PHP_SELF'";
$o_result2 = mysql_db_query($dbname,$o_sql2);

$o_user = mysql_num_rows($o_result2);

mysql_close();
?>