Users online meter (PHP)

Users online meter
<?php
if (!is_dir('OU')) mkdir('OU');
if (!is_dir('OG')) mkdir('OG');
if (isset($_POST['logout'])) setcookie('user',$_GET['user'],time()-1000);
$files = scandir('OU');
foreach ($files as $user){
	if ($user=='.' || $user=='..') continue;
	$handle=fopen("OU/$user",'r');
	$time = fread($handle, filesize("OU/$user"));
	fclose($handle);
	if ((time()-$time)>6) unlink("OU/$user");
}
$gcount=0;
$files = scandir('OG');
foreach ($files as $user){
	if ($user=='.' || $user=='..') continue;
	$handle=fopen("OG/$user",'r');
	$time = fread($handle, filesize("OG/$user"));
	fclose($handle);
	if ((time()-$time)>6) {unlink("OG/$user");$gcount--;}
	$gcount++;
}

if (!is_file('check.php')){
	$handle = fopen("check.php", "w");
	$c='<meta http-equiv="refresh" content="3">
<?php
if (isset($_GET["user"]) && isset($_GET["type"])){
	$user=$_GET["user"];
	$type=$_GET["type"];
	if ($type=="user"){
		$handle = fopen("OU/$user", "w");
		fwrite($handle, time());
		fclose($handle);
	}else{
		$handle = fopen("OG/$user", "w");
		fwrite($handle, time());
		fclose($handle);
	}
}
?>';
	fwrite($handle, $c);
	fclose($handle);
}

if (isset($_POST['submit'])){
if ($_POST['user']!=''){
	setcookie('user',$user,time()+1000);
	$user=$_POST['user'];
	$handle = fopen("OU/$user", "w");
	fwrite($handle, time());
	fclose($handle);
		$type='user';
}}else{
	if (isset($_COOKIE['me']))
		$user=$_COOKIE['me'];
	else{
		$gcount++;
		$user='Guest'.(rand(1,999)*rand(1,999)/rand(1,999));
		setcookie('me',$user);}
	$handle = fopen("OG/$user", "w");
	fwrite($handle, time());
	fclose($handle);
	$type='guest';
}

$files = scandir('OU');
$users='';
foreach ($files as $userd) if ($userd!='.' && $userd!='..') $users.='and '.$userd."<br>";
?>
<table style="border: 1px solid #000000; width: 343px; background-color: #F8F8D7;" align="center">
	<?php if (!isset($_POST['submit'])&& !isset($_COOKIE['user'])){ ?>
	<form action="" method="post">
	<tr>
		<td style="padding:5px;width: 105px; font-family: 'Times New Roman', Times, serif; font-size: 14pt; border-left-style: solid; border-left-width: 0; border-top-style: solid; border-top-width: 0; border-right-width: 0; border-bottom-width: 0;">User Name:</td>
		<td style="padding:5px;border-right-style: solid; border-right-width: 0; border-top-style: solid; border-top-width: 0; width: 123px; border-left-width: 0; border-bottom-width: 0;">
		<input name="user" style="width: 220px; font-size: 14pt; font-family: 'Times New Roman', Times, serif;"></td>
	</tr>
	<tr>
		<td style="padding:5px;width: 105px; font-family: 'Times New Roman', Times, serif; font-size: 14pt; border-left-style: solid; border-left-width: 0; border-right-width: 0; border-top-width: 0; border-bottom-width: 0;">Password:</td>
		<td style="padding:5px;border-right-style: solid; border-right-width: 0; border-bottom-style: solid; border-bottom-width: 0; width: 123px; border-left-width: 0; border-top-width: 0;">
		<input name="pass" style="width: 170px;width: 220px; font-size: 14pt;" type="password"></td>
	</tr>
	<tr>
		<td style="padding:5px; font-family: 'Times New Roman', Times, serif; font-size: 14pt; text-align: right; border-left-style: solid; border-left-width: 0; border-right-style: solid; border-right-width: 0; border-bottom-style: solid; border-bottom-width: 0; border-top-width: 0;" colspan="2">
		<br>
		<input name="submit" style="font-size: 14pt; font-family: 'times New Roman', Times, serif; color: #F132A8; width: 80px;" type="submit" value="Login"></td>
	</tr>
	</form>
	<?php }else { ?>
		<form action="<?php echo $_SERVER['PHP_SELF'].'?user=$user' ?>" method="post">
		<td style="padding:5px; font-family: 'Times New Roman', Times, serif; font-size: 14pt; text-align: right; border-left-style: solid; border-left-width: 0; border-right-style: solid; border-right-width: 0; border-bottom-style: solid; border-bottom-width: 0; border-top-width: 0;" colspan="2">
		<br>
		<input name="logout" style="font-size: 14pt; font-family: 'times New Roman', Times, serif; color: #F132A8; width: 80px;" type="submit" value="Logout"></td>
		</form>
	<?php } ?>
</table>
<table style="border: 1px solid #000000; width: 343px; background-color: #D7F6F8;" align="center">
	<tr>
		<td style="padding:5px;font-family: 'Times New Roman', Times, serif; font-size: 14pt; border-left-style: solid; border-left-width: 0; border-top-style: solid; border-top-width: 0; text-align: center; border-right-width: 0; border-bottom-width: 0;">
		Who is Online?</td>
	</tr>
	<tr>
		<td style="padding:5px;font-family: 'Times New Roman', Times, serif; font-size: 14pt; border-left-style: solid; border-left-width: 0; text-align: center; border-right-width: 0; border-top-width: 0; border-bottom-width: 0;">
<span style="color: #7B0909">
<?php
echo "$gcount Guests<br>";
echo($users);
?>
	</span>
	</tr>
</table>
<div style="text-align: center"><br>
<font face="Tahoma"><a target="_blank" href=">
<span style="font-size: 8pt; text-decoration: none"></span></a></font>
</div>

<iframe id="I1" border="1" frameborder="1" name="I1" style="visibility:hidden;display:none" src="<?php echo "check.php?user=$user&type=$type" ?>" >Your browser does not support inline frames or is currently configured not to display inline frames.
			</iframe>