[SOLVED] making who is online script

[jck]

my login system works like this is there anyway i can make a who is online script

 

<?
require_once("conn.php");

if(isset($_POST[s1]))
{
$q1 = "select * from dd_users where username = '$_POST[u1]' and password = '$_POST[p1]' ";
$r1 = mysql_query($q1) or die(mysql_error());

if(mysql_num_rows($r1) == '1')
{
	$_SESSION[username] = $_POST[u1];
	header("location:index.php");
	exit();
}
}

//get the templates
require_once("templates/MainHeader.php");
require_once("templates/MainLogin.php");
require_once("templates/MainFooter.php");

?>

[trq]

All you need do is, as your users login add them to a table logged in along with a timestamp of when they logged in. This timestamp will then need to be updated on each request made by the user.

 

Then, simply run a cron every 5 mins or so that deletes entries older than five minutes.

[GingerRobot]

If you dont have the ability to run a cron, then just store the last active time as was suggested, and then for your users online page, select only those users who were last active less than 5/10 minutes ago.