Show users currently online

[[!ListUsers? &minutes=`15`]]

<?php
/* ListUsers Snippet */
$minutes = $modx->getOption('minutes', $scriptProperties, 20);
$timetocheck = (time()-(60 * $minutes)) + $serverOffset;
$c = $modx->newQuery('modActiveUser');
$c->where(array('lasthit:>' => $timetocheck));
$c->sortby($modx->getSelectColumns('modActiveUser','modActiveUser','',array('username')),'ASC');
$ausers = $modx->getCollection('modActiveUser',$c);

$output = "<h3>Current Users</h3>\n<ul>";

foreach($ausers as $auser) {
   $output .= "\n    <li>" . $auser->get('username') . '</li>';
}

$output .= "\n</ul>";

return $output;

<?php
$allUsers = $modx->getCollection('modUser');

$count = 0;

foreach ($allUsers as $aUser) {
   if ($aUser->hasSessionContext('web') ) {
       $output .= "\n    <li>" . $aUser->get('userName') . '</li>';
       $count++;
   }
}

if ($count) {
   return "\n<ul>" . $output . "\n</ul>";
} else {
   return '<p>No Users online</p>';
}