var oldLink = null;
// code to change the active stylesheet
function setActiveStyleSheet(link, title) {
  var i, a, main;
  for(i=0; (a = document.getElementsByTagName("link")[i]); i++) {
	if(a.getAttribute("rel").indexOf("style") != -1 && a.getAttribute("title")) {
	  a.disabled = true;
	  if(a.getAttribute("title") == title) a.disabled = false;
	}
  }
  if (oldLink) oldLink.style.fontWeight = 'normal';
  oldLink = link;
  link.style.fontWeight = 'bold';
  return false;
}

// This function gets called when the end-user clicks on some date.
function selected(cal, date) {
  cal.sel.value = date; // just update the date in the input field.
  if (cal.dateClicked && (cal.sel.id == "sel1" || cal.sel.id == "sel3"))
	// if we add this call we close the calendar on single-click.
	// just to exemplify both cases, we are using this only for the 1st
	// and the 3rd field, while 2nd and 4th will still require double-click.
	cal.callCloseHandler();
}

// And this gets called when the end-user clicks on the _selected_ date,
// or clicks on the "Close" button.  It just hides the calendar without
// destroying it.
function closeHandler(cal) {
  cal.hide();                        // hide the calendar
//  cal.destroy();
  calendar = null;
}

// This function shows the calendar under the element having the given id.
// It takes care of catching "mousedown" signals on document and hiding the
// calendar if the click was outside.
function showCalendar(id, format, showsTime, showsOtherMonths) {
  var el = document.getElementById(id);
  if (calendar != null) {
	// we already have some calendar created
	calendar.hide();                 // so we hide it first.
  } else {
	// first-time call, create the calendar.
	var cal = new Calendar(true, null, selected, closeHandler);
	// uncomment the following line to hide the week numbers
	// cal.weekNumbers = false;
	if (typeof showsTime == "string") {
	  cal.showsTime = true;
	  cal.time24 = (showsTime == "24");
	}
	if (showsOtherMonths) {
	  cal.showsOtherMonths = true;
	}
	calendar = cal;                  // remember it in the global var
	cal.setRange(1900, 2070);        // min/max year allowed.
	cal.create();
  }
  calendar.setDateFormat(format);    // set the specified date format
  calendar.parseDate(el.value);      // try to parse the text in field
  calendar.sel = el;                 // inform it what input field we use

  // the reference element that we pass to showAtElement is the button that
  // triggers the calendar.  In this example we align the calendar bottom-right
  // to the button.
  calendar.showAtElement(el.nextSibling, "Br");        // show the calendar

  return false;
}

var MINUTE = 60 * 1000;
var HOUR = 60 * MINUTE;
var DAY = 24 * HOUR;
var WEEK = 7 * DAY;

// If this handler returns true then the "date" given as
// parameter will be disabled.  In this example we enable
// only days within a range of 10 days from the current
// date.
// You can use the functions date.getFullYear() -- returns the year
// as 4 digit number, date.getMonth() -- returns the month as 0..11,
// and date.getDate() -- returns the date of the month as 1..31, to
// make heavy calculations here.  However, beware that this function
// should be very fast, as it is called for each day in a month when
// the calendar is (re)constructed.
function isDisabled(date) {
  var today = new Date();
  return (Math.abs(date.getTime() - today.getTime()) / DAY) > 10;
}

function flatSelected(cal, date) {
  var el = document.getElementById("preview");
  el.innerHTML = date;
}

function showFlatCalendar() {
  var parent = document.getElementById("display");

  // construct a calendar giving only the "selected" handler.
  var cal = new Calendar(true, null, flatSelected);

  // hide week numbers
  cal.weekNumbers = false;

  // We want some dates to be disabled; see function isDisabled above
  cal.setDisabledHandler(isDisabled);
  cal.setDateFormat("%A, %B %e");

  // this call must be the last as it might use data initialized above; if
  // we specify a parent, as opposite to the "showCalendar" function above,
  // then we create a flat calendar -- not popup.  Hidden, though, but...
  cal.create(parent);

  // ... we can show it here.
  cal.show();
}


function validateDate(myDate) {
	msg = checkDate(myDate);
	if (msg != "true") {
		alert(msg);
		myDate.focus();
		myDate.select();
	}
}

function checkDate(myDate)
{	var OK = "true";
		myDate = myDate.value;
		if (myDate == "")
			return OK;
		var FirstStop = myDate.indexOf("-");
		if (FirstStop < 1)
		{
			OK = "Wrond Date Format. Please fill in a date in this format:\ndd-mm-yyyy";  
			return OK;
		}
		myDay = myDate.substr(0, FirstStop);
		myDay = parseInt(myDay, 10);
		if (myDay<1 || myDay>31 || isNaN(myDay)) 
		{
			OK = "Wrond Date. Please fill in a date in this format:\ndd-mm-yyyy";  
			return OK;
		}
		var SecondStop = myDate.indexOf("-", FirstStop + 1);
		if (SecondStop<FirstStop) 
		{
			OK = "Wrond Date. Please fill in a date in this format:\ndd-mm-yyyy";  
			return OK;
		}
		myMonth = myDate.substr(FirstStop+1,SecondStop-FirstStop-1);
		myMonth = parseInt(myMonth,10);
		if (myMonth<1 || myMonth>12 || isNaN(myMonth)) 
		{
			OK="Wrond Date Format. Please fill in a date in this format:\ndd-mm-yyyy";  
			return OK;
		}
		myYear=myDate.substr(SecondStop+1,myDate.length-SecondStop-1);
		if (myYear.length==2) 
		{	if (myYear<"30") 
			{	myYear="20" + myYear    } 
			else 
			{	myYear="19" + myYear	} 
		}; 
		if (isNaN(myYear)) {
			OK="Wrong year"; 
			return OK;
		}
		myYear=parseInt(myYear, 10);
		if (myMonth==4 || myMonth==6 || myMonth==9 || myMonth==11)
		{	if (myDay==31) 
			{	OK="This month has only 30 days.\ndd-mm-yyyy"; 
				return OK;
			}
		} 
		if (myMonth==2) 
		{	var Disekto=parseInt(myYear/4,10) 
			if (myDay>29) 
			{	OK="February does not have " + myDay + " days."; 
				return OK;
			}
			if (myDay==29 && ((myYear/4)!=Disekto))
			{	OK="February of " + myYear + " does not have " + myDay + " days."; 
				return OK;
			}
		}
	return OK;
}