function get_state_prov(){
    new Ajax.Request('/products/ajax_state_request/', { 
    method: 'post',
    parameters: $H({'country':$('id_country').getValue()}),
    onSuccess: function(transport) {
        var e = $('id_state_or_Province')
        if(transport.responseText)
            e.update(transport.responseText)
    }
    }); // end new Ajax.Request
}