var departdatecal;
    var returndatecal;

    function calendarInstall() {
            var departdatecaloptions = Object.extend({}, calendar.DefaultTextBehavior);

            Object.extend(departdatecaloptions,
                    {
                            divsToHide     : [ 'passenger_box' ],
                            changeCallback : departCalendarDateChange
                    });

            departdatecal = new calendar.Calendar('departdate', departdatecaloptions);

            returndatecal = new calendar.Calendar('returndate');

            Event.observe($('departdate'), 'blur', departdatecal.blur.bindAsEventListener(departdatecal));

            Event.observe($('returndate'), 'blur', returndatecal.blur.bindAsEventListener(returndatecal));
    }

    function departCalendarDateChange(d) {
            returndatecal.resetStartDate(d);
    }