function addDays(date, dayAdd) {
	millisec = (dayAdd) * 86400000;
	newTime = date.getTime() + millisec;
	return new Date(newTime);
}

function setEndNight() {
	if (!isNaN(Number (document.forms[0].nights.value)) ){
		var dataEnd =  new Date();
		var sDayVal  = Number(document.forms[0].arr_date[document.forms[0].arr_date.selectedIndex].value);
		var sYearVal = Number(document.forms[0].arr_year[document.forms[0].arr_year.selectedIndex].value);
		var sMonthVal= Number(document.forms[0].arr_mon[document.forms[0].arr_mon.selectedIndex].value);
		//arrive_date.innerText=this.aryGiorni[setWeekDay(sYearVal,sMonthVal,sDayVal)];
		var dataStart = new Date(sYearVal,sMonthVal-1,sDayVal,12,00,00);

		dataEnd = addDays (dataStart, Number(document.forms[0].nights.value));
//		dataEnd.setDate(dataStart.getDate() + Number(document.forms[0].nights.value));
		document.forms[0].dep_date.value=dataEnd.getDate();
		document.forms[0].dep_mon.value=dataEnd.getMonth()+1;
		document.forms[0].dep_year.value=dataEnd.getFullYear();


	} else {
			document.forms[0].nights.value="0";
			alert ("Invalid Night number");
		}
	return true;
}