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/%m/%d");

	param_default("daFormat",       "%Y/%m/%d");

	param_default("singleClick",    true);

	param_default("disableFunc",    null);

	param_default("dateStatusFunc", params["disableFunc"]);	// takes precedence if both are defined

	param_default("dateText",       null);

	param_default("firstDay",       null);

	param_default("align",          "Br");

	param_default("range",          [1900, 2999]); //IMPORTANTE

	param_default("weekNumbers",    false);

	param_default("flat",           null);

	param_default("flatCallback",   null);

	param_default("onSelect",       false);

	param_default("onClose",        null);

	param_default("onUpdate",       null);

	param_default("date",           null);

	param_default("showsTime",      false);

	param_default("timeFormat",     "24");

	param_default("electric",       true);

	param_default("step",           2);

	param_default("position",       null);

	param_default("cache",          false);

	param_default("showOthers",     false);

	param_default("multiple",       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.multiple || 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) {

		var p = cal.params;

		var update = (cal.dateClicked || p.electric);

		if (update && p.inputField) {

			p.inputField.value = cal.date.print(p.ifFormat);

			if (typeof p.inputField.onchange == "function")

				p.inputField.onchange();

		}

		if (update && p.displayArea)

			p.displayArea.innerHTML = cal.date.print(p.daFormat);

		if (update && typeof p.onUpdate == "function")

			p.onUpdate(cal);

		if (update && p.flat) {

			if (typeof p.flatCallback == "function")

				p.flatCallback(cal);

		}

		if (update && p.singleClick && cal.dateClicked)

			cal.callCloseHandler();

	};



	if (params.flat != null) {

		if (typeof params.flat == "string")

			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.firstDay, params.date, params.onSelect || onSelect);

		cal.showsOtherMonths = params.showOthers;

		cal.showsTime = params.showsTime;

		cal.time24 = (params.timeFormat == "24");

		cal.params = params;

		cal.weekNumbers = params.weekNumbers;

		cal.setRange(params.range[0], params.range[1]);

		cal.setDateStatusHandler(params.dateStatusFunc);

		cal.getDateText = params.dateText;

		if (params.ifFormat) {

			cal.setDateFormat(params.ifFormat);

		}

		if (params.inputField && typeof params.inputField.value == "string") {

			cal.parseDate(params.inputField.value);

		}

		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;

		var cal = window.calendar;

		if (dateEl)

			params.date = Date.parseDate(dateEl.value || dateEl.innerHTML, dateFmt);

		if (!(cal && params.cache)) {

			window.calendar = cal = new Calendar(params.firstDay,

							     params.date,

							     params.onSelect || onSelect,

							     params.onClose || function(cal) { cal.hide(); });

			cal.showsTime = params.showsTime;

			cal.time24 = (params.timeFormat == "24");

			cal.weekNumbers = params.weekNumbers;

			mustCreate = true;

		} else {

			if (params.date)

				cal.setDate(params.date);

			cal.hide();

		}

		if (params.multiple) {

			cal.multiple = {};

			for (var i = params.multiple.length; --i >= 0;) {

				var d = params.multiple[i];

				var ds = d.print("%Y%m%d");

				cal.multiple[ds] = d;

			}

		}

		cal.showsOtherMonths = params.showOthers;

		cal.yearStep = params.step;

		cal.setRange(params.range[0], params.range[1]);

		cal.params = params;

		cal.setDateStatusHandler(params.dateStatusFunc);

		cal.getDateText = params.dateText;

		cal.setDateFormat(dateFmt);

		if (mustCreate)

			cal.create();

		cal.refresh();

		if (!params.position)

			cal.showAtElement(params.button || params.displayArea || params.inputField, params.align);

		else

			cal.showAt(params.position[0], params.position[1]);

		return false;

	};



	return cal;

};