function arvDate(form) {

  form.x_arrival_date.value = form.arrival_month.value + "-" + form.arrival_day.value + "-" + form.arrival_year.value;

 }

 function depDate(form) {

  form.x_departure_date.value = form.departure_month.value + "-" + form.departure_day.value + "-" + form.departure_year.value;

 }