code: protected function getDatalistOptions()
  	{
  		$strGroups = '';
  
  		if (!$this->User->isAdmin)
  		{
  			// No allowed member groups
  			if (empty($this->User->amg) || !\is_array($this->User->amg))
  			{
  				header('Content-type: application/json');
  				die(json_encode(array()));
  			}
  
  			$arrGroups = array();
  
  			foreach ($this->User->amg as $intGroup)
  			{
  				$arrGroups[] = '%"' . (int) $intGroup . '"%';
  			}
  
  			$strGroups = " AND (groups LIKE '" . implode("' OR GROUPS LIKE '", $arrGroups) . "')";
  		}
  
  		$arrUsers = array();
  		$time = Date::floorToMinute();
  
  		// Get the active front end users
  		$objUsers = $this->Database->prepare("SELECT username FROM tl_member WHERE username LIKE ?$strGroups AND login='1' AND disable!='1' AND (start='' OR start<='$time') AND (stop='' OR stop>'" . ($time + 60) . "') ORDER BY username")
  								   ->limit(10)
  								   ->execute(str_replace('%', '', Input::post('value')) . '%');
  
  		if ($objUsers->numRows)
  		{
  			$arrUsers = $objUsers->fetchEach('username');
  		}
  
  		header('Content-type: application/json');
  		die(json_encode($arrUsers));
  	}
docs: Find ten matching usernames and return them as JSON