$mobile_device = false;
$user_agent = $_SERVER['HTTP_USER_AGENT'];
$mobile_agents = array(
    'iPhone',            // Apple iPhone
    'iPod',              // Apple iPod touch
    'Android',           // 1.5+ Android
    'Windows Phone',     // Windows Phone 7+
    'Windows CE',        // Windows CE
    'Symbian',           // Symbian S60
    'Opera Mini',        // Opera Mini
    'BlackBerry',        // BlackBerry
    'Opera Mobi',        // Opera Mobile
    'PalmSource'         // PalmSource
);
foreach ($mobile_agents as $device) {
    if (stristr($user_agent, $device)) {
        $mobile_device = true;
        break;
    }
}
if ($mobile_device) {
 return true;
} else {
  return false;
}