function roll_on(idel,chi) {
		idel.src = "./impianto/immagini/bt_sx"+chi+"_on.jpg";
}

function roll_off(idel,chi) {
		idel.src = "./impianto/immagini/bt_sx"+chi+"_off.jpg";
}
function getBlank (form, stdValue){
	if (form.value == stdValue){
		form.value = '';
		}
	return true;
}