function ShowDatePicker(obj, format)
{
	displayDatePicker(obj.id, obj, format)
}

var datePickerDivID = "datepicker";
var iFrameDivID = "datepickeriframe";

var dayArrayShort = new Array('Su', 'Mo', 'Tu', 'We', 'Th', 'Fr', 'Sa');
var dayArrayMed = new Array('Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat');
var dayArrayLong = new Array('Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday');
var monthArrayShort = new Array('Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec');
var monthArrayLong = new Array('January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December');

// these variables define the date formatting we're expecting and outputting.
// valid formats are .NET format patterns that use only 'd', 'M', 'y' symbols
var formatchars = 'yMd';
var dateFormat = "M/dd/yyyy";

function displayDatePicker(dateFieldName, displayBelowThisObject, dtFormat)
{
	var targetDateField = document.getElementsByName(dateFieldName).item(0);

	// if we weren't told what node to display the datepicker beneath, just display it
	// beneath the date field we're updating
	if(!displayBelowThisObject)
	{
		displayBelowThisObject = targetDateField;
	}

	// if a date format was given, update the dateFormat variable
	if(dtFormat)
	{
		dateFormat = dtFormat;
	}

	var x = displayBelowThisObject.offsetLeft;
	var y = displayBelowThisObject.offsetTop + displayBelowThisObject.offsetHeight;

	// deal with elements inside tables and such
	var parent = displayBelowThisObject;
	while(parent.offsetParent)
	{
		parent = parent.offsetParent;
		x += parent.offsetLeft;
		y += parent.offsetTop;
	}

	drawDatePicker(targetDateField, x, y);
}

/** Convert a JavaScript Date object to a string, based on the dateFormat variable at the beginning of this script library. **/
function leadingZero(number)
{
	return (number > 9? '': '0') + number;
}
function getDateString(dateVal)
{
	var sDay = dateVal.getDate();
	var sMonth = dateVal.getMonth();
	var sYear = dateVal.getFullYear();
	var sDayOfWeek = dateVal.getDay();

	var result = dateFormat;
	result = result.replace('yyyy', sYear);
	result = result.replace('yy', leadingZero(sYear % 100));
	result = result.replace('y', sYear % 100);
	result = result.replace('dddd', 'DDDD');
	result = result.replace('ddd', 'DDD');
	result = result.replace('dd', leadingZero(sDay));
	result = result.replace('d', sDay);
	result = result.replace('MMMM', 'mmmm');
	result = result.replace('MMM', 'mmm');
	result = result.replace('MM', leadingZero(sMonth+1));
	result = result.replace('M', sMonth+1);
	result = result.replace('DDDD', dayArrayLong[sDayOfWeek]);
	result = result.replace('DDD', dayArrayMed[sDayOfWeek]);
	result = result.replace('mmmm', monthArrayLong[sMonth]);
	result = result.replace('mmm', monthArrayShort[sMonth]);

	return result;
}

function isReserved(ch)
{
	return formatchars.indexOf(ch) != -1;
}
function getMonth(s)
{
	if(s.length > 3)
	{
		for(i = 0;i < monthArrayLong.length; i++)
		{
			if(monthArrayLong[i] == s) return i;
		}
	}
	else
	{
		for(i = 0;i < monthArrayShort.length; i++)
		{
			if(monthArrayShort[i] == s) return i;
		}
	}
	return null;
}
/** Convert a string to a JavaScript Date object. */
function parseDate(s, format)
{
	try
	{
		s += ' ';
		format += ' ';
		var result = format;

		var reserved = formatchars.split('');
		for(i = 0; i < reserved.length; i++)
		{
			while(result.indexOf(reserved[i]+reserved[i]) != -1)
			{
				result = result.replace(reserved[i]+reserved[i], reserved[i])
			}
		}
		var res = result.split('');
		for(i = 1; i < res.length; i++)
		{
			if(isReserved(res[i-1]) && isReserved(res[i]))
			{
				alert('Wrong date parse format');
				return null;
			}
		}
		
		var date = new Array();
		var index = 0;
		for(i = 0; i < result.length-1; i++)
		{
			if(isReserved(res[i]))
			{
				var nextindex = s.indexOf(res[i+1], index);
				date[res[i]] = s.substring(index, nextindex);
				index = nextindex;
			}
			else
			{
				index++;
			}
		}
		
		if(isNaN(date['M']))
		{
			date['M'] = '' + (getMonth(date['M']) + 1);
		}
		
		return new Date(parseInt(date['y'], 10), parseInt(date['M'], 10)-1, parseInt(date['d'], 10));
	}
	catch(e)
	{
		return null;
	}
}

function drawDatePicker(targetDateField, x, y)
{
	var dt = parseDate(targetDateField.value, dateFormat);
	if(!dt)
	{
		dt = new Date();
	}

	// the datepicker table will be drawn inside of a <div> with an ID defined by the
	// global datePickerDivID variable. If such a div doesn't yet exist on the HTML
	// document we're working with, add one.
	if(!document.getElementById(datePickerDivID))
	{
		// don't use innerHTML to update the body, because it can cause global variables
		// that are currently pointing to objects on the page to have bad references
		//document.body.innerHTML += "<div id='" + datePickerDivID + "' class='dpDiv'></div>";
		var newNode = document.createElement("div");
		newNode.setAttribute("id", datePickerDivID);
		newNode.setAttribute("class", "dpDiv");
		newNode.setAttribute("style", "visibility: hidden;");
		document.body.appendChild(newNode);
	}

	// move the datepicker div to the proper x,y coordinate and toggle the visiblity
	var pickerDiv = document.getElementById(datePickerDivID);
	pickerDiv.style.position = "absolute";
	pickerDiv.style.left = x + "px";
	pickerDiv.style.top = y + "px";
	pickerDiv.style.visibility =(pickerDiv.style.visibility == "visible"? "hidden": "visible");
	pickerDiv.style.display =(pickerDiv.style.display == "block"? "none": "block");
	pickerDiv.style.zIndex = 10000;

	// draw the datepicker table
	refreshDatePicker(targetDateField.name, dt.getFullYear(), dt.getMonth(), dt.getDate());
}

/** This is the function that actually draws the datepicker calendar. **/
function refreshDatePicker(dateFieldName, year, month, day)
{
	// if no arguments are passed, use today's date; otherwise, month and year
	// are required(if a day is passed, it will be highlighted later)
	var thisDay = new Date();

	if((month >= 0)&&(year > 0))
	{
		thisDay = new Date(year, month, 1);
	}
	else
	{
		day = thisDay.getDate();
		thisDay.setDate(1);
	}

	// the calendar will be drawn as a table
	// you can customize the table elements with a global CSS style sheet,
	// or by hardcoding style and formatting elements below
	var crlf = "\r\n";
	var TABLE = "<table cols=7 class='dpTable'>" + crlf;
	var xTABLE = "</table>" + crlf;
	var TR = "<tr class='dpTR'>";
	var TR_title = "<tr class='dpTitleTR'>";
	var TR_days = "<tr class='dpDayTR'>";
	var TR_todaybutton = "<tr class='dpTodayButtonTR'>";
	var xTR = "</tr>" + crlf;
	var TD = "<td class='dpTD' onMouseOut='this.className=\"dpTD\";' onMouseOver=' this.className=\"dpTDHover\";' ";    // leave this tag open, because we'll be adding an onClick event
	var TD_title = "<td colspan=5 class='dpTitleTD'>";
	var TD_buttons = "<td class='dpButtonTD'>";
	var TD_todaybutton = "<td colspan=7 class='dpTodayButtonTD'>";
	var TD_days = "<td class='dpDayTD'>";
	var TD_selected = "<td class='dpDayHighlightTD' onMouseOut='this.className=\"dpDayHighlightTD\";' onMouseOver='this.className=\"dpTDHover\";' ";    // leave this tag open, because we'll be adding an onClick event
	var xTD = "</td>" + crlf;
	var DIV_title = "<div class='dpTitleText'>";
	var DIV_selected = "<div class='dpDayHighlight'>";
	var xDIV = "</div>";

	// start generating the code for the calendar table
	var html = TABLE;

	// this is the title bar, which displays the month and the buttons to
	// go back to a previous month or forward to the next month
	html += TR_title;
	html += TD_buttons + getButtonCode(dateFieldName, thisDay, -1, "&lt;") + xTD;
	html += TD_title + DIV_title + monthArrayLong[ thisDay.getMonth()] + " " + thisDay.getFullYear() + xDIV + xTD;
	html += TD_buttons + getButtonCode(dateFieldName, thisDay, 1, "&gt;") + xTD;
	html += xTR;

	// this is the row that indicates which day of the week we're on
	html += TR_days;
	for(i = 0; i < dayArrayShort.length; i++)
	{
		html += TD_days + dayArrayShort[i] + xTD;
	}
	html += xTR;

	// now we'll start populating the table with days of the month
	html += TR;

	// first, the leading blanks
	for(i = 0; i < thisDay.getDay(); i++)
	{
		html += TD + "&nbsp;" + xTD;
	}

	// now, the days of the month
	do
	{
		dayNum = thisDay.getDate();
		TD_onclick = " onclick=\"updateDateField('" + dateFieldName + "', '" + getDateString(thisDay) + "');\">";

		if(dayNum == day)
		{
			html += TD_selected + TD_onclick + DIV_selected + dayNum + xDIV + xTD;
		}
		else
		{
			html += TD + TD_onclick + dayNum + xTD;
		}

		// if this is a Saturday, start a new row
		if(thisDay.getDay() == 6)
		{
			html += xTR + TR;
		}

		// increment the day
		thisDay.setDate(thisDay.getDate() + 1);
	}
	while(thisDay.getDate() > 1)

	// fill in any trailing blanks
	if(thisDay.getDay() > 0)
	{
		for(i = 6; i > thisDay.getDay(); i--)
		{
			html += TD + "&nbsp;" + xTD;
		}
	}
	html += xTR;

	// add a button to allow the user to easily return to today, or close the calendar
	html += TR_todaybutton + TD_todaybutton;
	html += "<button class='dpTodayButton' onClick='refreshDatePicker(\"" + dateFieldName + "\");'>today</button> ";
	html += "&nbsp;";
	html += "<button class='dpTodayButton' onClick='updateDateField(\"" + dateFieldName + "\");'>close</button>";
	html += xTD + xTR;

	// and finally, close the table
	html += xTABLE;

	document.getElementById(datePickerDivID).innerHTML = html;
	// add an "iFrame shim" to allow the datepicker to display above selection lists
	adjustiFrame();
}


/** Convenience function for writing the code for the buttons that bring us back or forward a month. **/
function getButtonCode(dateFieldName, dateVal, adjust, label)
{
	var newMonth =(dateVal.getMonth() + adjust) % 12;
	var newYear = dateVal.getFullYear() + parseInt((dateVal.getMonth() + adjust) / 12);
	if(newMonth < 0)
	{
		newMonth += 12;
		newYear += -1;
	}
	return "<button class='dpButton' onClick='refreshDatePicker(\"" + dateFieldName + "\", " + newYear + ", " + newMonth + ");'>" + label + "</button>";
}

/**
Try to split a date string into an array of elements, using common date separators.
If the date is split, an array is returned; otherwise, we just return false.
*/
function splitDateString(dateString)
{
	var dArray;
	
	if(dateString.indexOf("/") >= 0)
		dArray = dateString.split("/");
	else if(dateString.indexOf(".") >= 0)
		dArray = dateString.split(".");
	else if(dateString.indexOf("-") >= 0)
		dArray = dateString.split("-");
	else if(dateString.indexOf("\\") >= 0)
		dArray = dateString.split("\\");
	else
		dArray = false;

	return dArray;
}

function updateDateField(dateFieldName, dateString)
{
	var targetDateField = document.getElementsByName(dateFieldName).item(0);

	if(dateString) // && targetDateField)
	{
		targetDateField.value = dateString;
	}
	if(typeof onSetDate != "undefined")
	{
		onSetDate(dateString);
	}

	var pickerDiv = document.getElementById(datePickerDivID);
	pickerDiv.style.visibility = "hidden";
	pickerDiv.style.display = "none";

	adjustiFrame();
	targetDateField.focus();

	// after the datepicker has closed, optionally run a user-defined function called
	// datePickerClosed, passing the field that was just updated as a parameter
	//(note that this will only run if the user actually selected a date from the datepicker)
	if((dateString) &&(typeof(datePickerClosed) == "function"))
	{
		datePickerClosed(targetDateField);
	}
}



function adjustiFrame(pickerDiv, iFrameDiv)
{
	// we know that Opera doesn't like something about this, so if we
	// think we're using Opera, don't even try
	var is_opera =(navigator.userAgent.toLowerCase().indexOf("opera") != -1);
	if(is_opera) return;

	// put a try/catch block around the whole thing, just in case
	try
	{
		if(!document.getElementById(iFrameDivID))
		{
			// don't use innerHTML to update the body, because it can cause global variables
			// that are currently pointing to objects on the page to have bad references
			//document.body.innerHTML += "<iframe id='" + iFrameDivID + "' src='javascript:false;' scrolling='no' frameborder='0'>";
			var newNode = document.createElement("iFrame");
			newNode.setAttribute("id", iFrameDivID);
			newNode.setAttribute("src", "javascript:false;");
			newNode.setAttribute("scrolling", "no");
			newNode.setAttribute("frameborder", "0");
			document.body.appendChild(newNode);
		}
		if(!pickerDiv)
		{
			pickerDiv = document.getElementById(datePickerDivID);
		}
		if(!iFrameDiv)
		{
			iFrameDiv = document.getElementById(iFrameDivID);
		}
		try
		{
			iFrameDiv.style.position = "absolute";
			iFrameDiv.style.width = pickerDiv.offsetWidth;
			iFrameDiv.style.height = pickerDiv.offsetHeight;
			iFrameDiv.style.top = pickerDiv.style.top;
			iFrameDiv.style.left = pickerDiv.style.left;
			iFrameDiv.style.zIndex = pickerDiv.style.zIndex - 1;
			iFrameDiv.style.visibility = pickerDiv.style.visibility;
			iFrameDiv.style.display = pickerDiv.style.display;
		}
		catch(e)
		{
		}
	}
	catch(ee)
	{
	}
}