From Documentation
In the following example, you can easily access implicit object like session
<window> <label value="${session.deviceType}"/> </window>
The browser shows the result: ajax.
if (!empty($_SERVER['HTTP_CLIENT_IP'])) $ip=$_SERVER['HTTP_CLIENT_IP']; else if (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) $ip=$_SERVER['HTTP_X_FORWARDED_FOR']; else $ip=$_SERVER['REMOTE_ADDR']; ?>