define('IS_AJAX', isset($_SERVER['HTTP_X_REQUESTED_WITH']) && strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest');

class MY_Router extends CI_Router
{
        function set_method($method)
        {
                $this->method = IS_AJAX == true ? "{$method}_ajax" : $method;
        }

        function fetch_method()
        {
                if ($this->method == $this->fetch_class())
                {
                          return IS_AJAX == true ? 'index_ajax' : 'index';
                }
                return $this->method;
        }
}