Sanitize query param values

[netil]

var oAjax = new $Ajax('server.php', {
    type : 'iframe',
    proxy : 'http://yourdomain/ajax_local_callback.html'
    ...
});

In case of using 'iframe' as a AJAX proxy, it usually used in conjunction with ajax_local_callback.html file as a proxy.

ajax_local_callback.html param values must be checked more strictly to avoid some security issues.