monthMaxDays	= [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
monthMaxDaysLeap= [31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
hideSelectTags = [];
function getRealYear(dateObj)
{
	return (dateObj.getYear() % 100) + (((dateObj.getYear() % 100) < 39) ? 2000 : 1900);
}
function getDaysPerMonth(month, year)
{
	if ((year % 4) == 0)
	{
		if ((year % 100) == 0 && (year % 400) != 0)
			return monthMaxDays[month];
	
		return monthMaxDaysLeap[month];
	}
	else
		return monthMaxDays[month];
}
function createCalender(year, month, day)
{
	var curDate = new Date();
	var curDay = curDate.getDate();
	var curMonth = curDate.getMonth();
	var curYear = getRealYear(curDate)
	if (!year)
	{
		var year = curYear;
		var month = curMonth;
	}
	var yearFound = 0;
	for (var i=0; i<document.getElementById('selectYear').options.length; i++)
	{
		if (document.getElementById('selectYear').options[i].value == year)
		{
			document.getElementById('selectYear').selectedIndex = i;
			yearFound = true;
			break;
		}
	}
	if (!yearFound)
	{
		document.getElementById('selectYear').selectedIndex = 0;
		year = document.getElementById('selectYear').options[0].value;		
	}
	document.getElementById('selectMonth').selectedIndex = month;
	var fristDayOfMonthObj = new Date(year, month, 1);
	var firstDayOfMonth = fristDayOfMonthObj.getDay();
	continu		= true;
	firstRow	= true;
	var x	= 0;
	var d	= 0;
	var trs = []
	var ti = 0;
	while (d <= getDaysPerMonth(month, year))
	{
		if (firstRow)
		{
			trs[ti] = document.createElement("TR");
			if (firstDayOfMonth > 0)
			{
				while (x < firstDayOfMonth)
				{
					trs[ti].appendChild(document.createElement("TD"));
					x++;
				}
			}
			firstRow = false;
			var d = 1;
		}
		if (x % 7 == 0)
		{
			ti++;
			trs[ti] = document.createElement("TR");
		}
		if (day && d == day)
		{
			var setID = 'calenderChoosenDay';
			var styleClass = 'choosenDay';
			var setTitle = 'this day is currently selected';
		}
		else if (d == curDay && month == curMonth && year == curYear)
		{
			var setID = 'calenderToDay';
			var styleClass = 'toDay';
			var setTitle = 'this day today';
		}
		else
		{
			var setID = false;
			var styleClass = 'normalDay';
			var setTitle = false;
		}
		var td = document.createElement("TD");
		td.className = styleClass;
		if (setID)
		{
			td.id = setID;
		}
		if (setTitle)
		{
			td.title = setTitle;
		}
		td.onmouseover = new Function('highLiteDay(this)');
		td.onmouseout = new Function('deHighLiteDay(this)');
		if (targetEl)
			td.onclick = new Function('pickDate('+year+', '+month+', '+d+')');
		else
			td.style.cursor = 'default';
		td.appendChild(document.createTextNode(d));
		trs[ti].appendChild(td);
		x++;
		d++;
	}
	return trs;
}

function showCalender(elPos, tgtEl)
{
	targetEl = false;

	if (document.getElementById(tgtEl))
	{
		targetEl = document.getElementById(tgtEl);
	}
	else
	{
		if (document.forms[0].elements[tgtEl])
		{
			targetEl = document.forms[0].elements[tgtEl];
		}
		else
		{
		}
	}
	var calTable = document.getElementById('calenderTable');
	var positions = [0,0];
	var positions = getParentOffset(elPos, positions);
	calTable.style.left = positions[0]+'px';
	calTable.style.top = positions[1]+'px';
	calTable.style.display='block';
	var matchDate = new RegExp('^([0-9]{2})-([0-9]{2})-([0-9]{4})$');
	var m = matchDate.exec(targetEl.value);
	if (m == null)
	{
		trs = createCalender(false, false, false);
		showCalenderBody(trs);
	}
	else
	{
		if (m[1].substr(0, 1) == 0)
			m[1] = m[1].substr(1, 1);
		if (m[2].substr(0, 1) == 0)
			m[2] = m[2].substr(1, 1);
		m[2] = m[2] - 1;
		trs = createCalender(m[3], m[2], m[1]);
		showCalenderBody(trs);
	}
	hideSelect(document.body, 1);
}
function showCalenderBody(trs)
{
	var calTBody = document.getElementById('calender');
	while (calTBody.childNodes[0])
	{
		calTBody.removeChild(calTBody.childNodes[0]);
	}
	for (var i in trs)
	{
		calTBody.appendChild(trs[i]);
	}
}
function setYears(sy, ey)
{
	var curDate = new Date();
	var curYear = getRealYear(curDate);
	if (sy)
		startYear = curYear;
	if (ey)
		endYear = curYear;
	document.getElementById('selectYear').options.length = 0;
	var j = 0;
	for (y=ey; y>=sy; y--)
	{
		document.getElementById('selectYear')[j++] = new Option(y, y);
	}
}
function hideSelect(el, superTotal)
{
	if (superTotal >= 100)
	{
		return;
	}

	var totalChilds = el.childNodes.length;
	for (var c=0; c<totalChilds; c++)
	{
		var thisTag = el.childNodes[c];
		if (thisTag.tagName == 'SELECT')
		{
			if (thisTag.id != 'selectMonth' && thisTag.id != 'selectYear')
			{
				var calenderEl = document.getElementById('calenderTable');
				var positions = [0,0];
				var positions = getParentOffset(thisTag, positions);
				var thisLeft	= positions[0];
				var thisRight	= positions[0] + thisTag.offsetWidth;
				var thisTop	= positions[1];
				var thisBottom	= positions[1] + thisTag.offsetHeight;
				var calLeft	= calenderEl.offsetLeft;
				var calRight	= calenderEl.offsetLeft + calenderEl.offsetWidth;
				var calTop	= calenderEl.offsetTop;
				var calBottom	= calenderEl.offsetTop + calenderEl.offsetHeight;
				if (
					(
						(thisLeft >= calLeft && thisLeft <= calRight)
							||
						(thisRight <= calRight && thisRight >= calLeft)
							||
						(thisLeft <= calLeft && thisRight >= calRight)
					)
						&&
					(
						(thisTop >= calTop && thisTop <= calBottom)
							||
						(thisBottom <= calBottom && thisBottom >= calTop)
							||
						(thisTop <= calTop && thisBottom >= calBottom)
					)
				)
				{
					hideSelectTags[hideSelectTags.length] = thisTag;
					thisTag.style.display = 'none';
				}
			}

		}
		else if(thisTag.childNodes.length > 0)
		{
			hideSelect(thisTag, (superTotal+1));
		}
	}
}
function closeCalender()
{
	for (var i=0; i<hideSelectTags.length; i++)
	{
		hideSelectTags[i].style.display = 'block';
	}
	hideSelectTags.length = 0;
	document.getElementById('calenderTable').style.display='none';
}
function highLiteDay(el)
{
	el.className = 'hlDay';
}
function deHighLiteDay(el)
{
	if (el.id == 'calenderToDay')
		el.className = 'toDay';
	else if (el.id == 'calenderChoosenDay')
		el.className = 'choosenDay';
	else
		el.className = 'normalDay';
}
function pickDate(year, month, day)
{
	month++;
	day	= day < 10 ? '0'+day : day;
	month	= month < 10 ? '0'+month : month;
	if (!targetEl)
	{
		alert('target for date is not set yet');
	}
	else
	{
		targetEl.value= year+'-'+month+'-'+day;
		closeCalender();
		readMap(year+'-'+month+'-'+day);
	}
}
function getParentOffset(el, positions)
{
	positions[0] += el.offsetLeft;
	positions[1] += el.offsetTop;
	if (el.offsetParent)
		positions = getParentOffset(el.offsetParent, positions);
	return positions;
}