var popupCalendar = null;

function showCalendar(id, format, showsTime, showsOtherMonths) {
	var el = document.getElementById(id);
	if (popupCalendar != null) {
		popupCalendar.hide();
	} else {
		var cal = new Calendar(1, null, calSelected, calCloseHandler);
		if (typeof showsTime == "string") {
			cal.showsTime = true;
			cal.time24 = (showsTime == "24");
		}
		if (showsOtherMonths) {
			cal.showsOtherMonths = true;
		}
		popupCalendar = cal;
		cal.setRange(1900, 2070);
		cal.create();
	}
	popupCalendar.setDateFormat(format);
	popupCalendar.parseDate(el.value);
	popupCalendar.sel = el;

	popupCalendar.showAtElement(el, "Br");

	return false;
}

function calSelected(cal, date) {
	cal.sel.value = date;
	if (cal.dateClicked && (cal.sel.id == "opt_due"))
	cal.callCloseHandler();
}

function calCloseHandler(cal) {
	cal.hide();
	popupCalendar = null;
}