Calendar.setup = function (params) {
	function param_default(pname, def) { if (typeof params[pname] == "undefined") { params[pname] = def; } };
	param_default("inputField",    null);
	param_default("displayArea",   null);
	param_default("button",        null);
	param_default("eventName",     "click");
	param_default("ifFormat",      "y/mm/dd");
	param_default("daFormat",      "y/mm/dd");
	param_default("singleClick",   true);
	param_default("disableFunc",   null);
	param_default("mondayFirst",   false);
	param_default("align",         "Bl");
	param_default("range",         [1900, 2999]);
	param_default("weekNumbers",   true);
	param_default("flat",          null);
	param_default("flatCallback",  null);
	var tmp = ["inputField", "displayArea", "button"];
	for (var i in tmp) {
		if (typeof params[tmp[i]] == "string") {
			params[tmp[i]] = document.getElementById(params[tmp[i]]);
		}
	}
	if (!(params.flat || params.inputField || params.displayArea || params.button)) {
		alert("Calendar.setup:\n  Nothing to setup (no fields found).  Please check your code");
		return false;
	}

	function onSelect(cal) {
		if (cal.params.flat) {
			if (typeof cal.params.flatCallback == "function") {
				cal.params.flatCallback(cal);
			} else {
				alert("No flatCallback given -- doing nothing.");
			}
			return false;
		}
		if (cal.params.inputField) {
			cal.params.inputField.value = cal.date.print(cal.params.ifFormat);
		}
		if (cal.params.displayArea) {
			cal.params.displayArea.innerHTML = cal.date.print(cal.params.daFormat);
		}
		if (cal.params.singleClick && cal.dateClicked) {
			cal.callCloseHandler();
		}
	};

	if (params.flat != null) {
		params.flat = document.getElementById(params.flat);
		if (!params.flat) {
			alert("Calendar.setup:\n  Flat specified but can't find parent.");
			return false;
		}
		var cal = new Calendar(params.mondayFirst, null, onSelect);
		cal.params = params;
		cal.weekNumbers = params.weekNumbers;
		cal.setRange(params.range[0], params.range[1]);
		cal.setDisabledHandler(params.disableFunc);
		cal.create(params.flat);
		cal.show();
		return false;
	}

	var triggerEl = params.button || params.displayArea || params.inputField;
	triggerEl["on" + params.eventName] = function() {
		var dateEl = params.inputField || params.displayArea;
		var dateFmt = params.inputField ? params.ifFormat : params.daFormat;
		var mustCreate = false;
		if (!window.calendar) {
			window.calendar = new Calendar(params.mondayFirst, null, onSelect, function(cal) { cal.hide(); });
			window.calendar.weekNumbers = params.weekNumbers;
			mustCreate = true;
		} else {
			window.calendar.hide();
		}
		window.calendar.setRange(params.range[0], params.range[1]);
		window.calendar.params = params;
		window.calendar.setDisabledHandler(params.disableFunc);
		window.calendar.setDateFormat(dateFmt);
		if (mustCreate) {
			window.calendar.create();
		}
		window.calendar.parseDate(dateEl.value || dateEl.innerHTML);
		window.calendar.refresh();
		window.calendar.showAtElement(params.displayArea || params.inputField, params.align);
		return false;
	};
};