Add Days in Date using Javascript

function AddDays(FromDate,Days) {

var dateFrom = new Date(dtF);

var numberOfDaysToAdd = parseInt(Days.value);

dateFrom.setDate(dateFrom.getDate() + numberOfDaysToAdd);

var dd = dateFrom.getDate();

var mm = dateFrom.getMonth() + 1;

var y = dateFrom.getFullYear();

var DateTo = mm + '/' + dd + '/' + y;

alert(DateTo);

}