 <script type="text/javascript">
            var startDate;
            var endDate;
            var ONEDAY = 3600 * 24;

            function resetDates() {
                startDate = endDate = null;
            }

            function filterDates1(cal) {
                var date = cal.date;
                startDate = date.getTime()

                if (endDate == null) {
                    Zapatec.Calendar.setup({
                        inputField     :    "arrivalDate",
                        button         :    "button8b",
                       ifFormat        :    "%d-%m-%Y",
                        date           :     startDate,
                        showsTime      :     false,
                        disableFunc    :    disallowDateBefore,
                        onUpdate       :    filterDates2
                    });
                }
            }

            function filterDates2(cal) {
                var date = cal.date;
                endDate = date.getTime()
            }
            function disallowDateBefore(date) {
                date = date.getTime();
                if ((startDate != null) && (date < (startDate + ONEDAY))) {

                    return true;
                }
                var now = new Date().getTime();
                if (date < (now - ONEDAY)) {

                    return true;
                }
                return false;
            }
            function disallowDateAfter(date) {
                date = date.getTime();
                if ((endDate != null) && (date > (endDate - ONEDAY))) {

                    return true;
                }

                var now = new Date().getTime();
                if (date < (now - ONEDAY)) {

                    return true;
                }
                return false;
            }

            Zapatec.Calendar.setup({
                inputField     :    "departure_date",
                button         :    "button8a",
                ifFormat       :    "%d-%m-%Y",
                showsTime      :     false,
                disableFunc    :    disallowDateAfter,
                onUpdate       :    filterDates1



            });
            Zapatec.Calendar.setup({
                inputField     :    "arrivalDate",
                button         :    "button8b",
                ifFormat       :    "%d-%m-%Y",
                showsTime      :     false,
                disableFunc    :    disallowDateBefore,
                onUpdate       :    filterDates2
            });

        </script>
