function pickDate(field)
	{
		var element = event.srcElement;
		if(!element) element = event.target;	
		var x = findPosX(element);
		var y = findPosY(element);	
		var datePick = new HDDatePicker();
		datePick.Show(x,y,
		function(date,weekSele)
		{
			field.value = date.getUTCFullYear() + "-" + (date.getMonth()<9?"0":"") + (date.getMonth()+1) + "-" + (date.getDate()<9?"0":"") + date.getDate();
			datePick.Close(); 
		});
	}
	
	Date.prototype.getWeek = function (dowOffset)
	{
		/*getWeek() was developed by Nick Baicoianu at MeanFreePath: http://www.meanfreepath.com */
		dowOffset = typeof(dowOffset) == 'int' ? dowOffset : 0; //default dowOffset to zero
		var newYear = new Date(this.getFullYear(),0,1);
		var day = newYear.getDay() - dowOffset; //the day of week the year begins on
		day = (day >= 0 ? day : day + 7);
		var daynum = Math.floor((this.getTime() - newYear.getTime() -
		(this.getTimezoneOffset()-newYear.getTimezoneOffset())*60000)/86400000) + 1;
		var weeknum;
		//if the year starts before the middle of a week
		if(day < 4)
		{
			weeknum = Math.floor((daynum+day-1)/7) + 1;
			if(weeknum > 52)
			{
				nYear = new Date(this.getFullYear() + 1,0,1);
				nday = nYear.getDay() - dowOffset;
				nday = nday >= 0 ? nday : nday + 7;
				/*if the next year starts before the middle of
				the week, it is week #1 of that year*/
				weeknum = nday < 4 ? 1 : 53;
			}
		}
		else
		{
			weeknum = Math.floor((daynum+day-1)/7);
		}
		return weeknum;
	};
	
	HDDatePicker = Class.create();

	HDDatePicker.prototype =
	{
		months : new Array("Jan","Feb","Mar","Apr","Maj","Jun","Jul","Aug","Sep","Okt","Nov","Dec"),
		div : null,
		startDate : null,
		callback : null,
		initialize : function()
		{
			this.div = document.createElement("DIV");
			this.div.style.position = "absolute";
			this.div.style.width = "193px";
			this.div.style.zIndex = "10000";
			this.div.style.background = "#ffffff";
			this.startDate = new Date();
			this.startDate.setDate(1);
		}
		,
		Show : function(x,y,clb)
		{
			this.callback = clb;
			this.div.style.left = x + "px";
			this.div.style.top = y + "px";
			this.Render();
			document.body.appendChild(this.div);
		},
		Render : function()
		{
			this.div.innerHTML = "";
			var table = document.createElement("table");
			table.cellSpacing = "0";
			table.cellPadding = "0";
			table.className = "datepopuptable";
			table.width = "100%";
			var tr = table.insertRow(-1);
			var td = tr.insertCell(-1);
			td.colSpan = 8;
			td.className = "datepickmenu";
			td.align = "right";  
			var link = document.createElement("a");
			link.href = "javascript:void(0)";
			link.className = "datepickclose";
			link.appendChild(document.createTextNode("X"));
			link.datePicker = this;
			link.onclick = function()
			{
			 	this.datePicker.Close();
			}
			td.appendChild(link);
			tr = table.insertRow(-1);
			td = tr.insertCell(-1);
			td.className = "datepickheader";
			td.appendChild(document.createTextNode(""));
			td = tr.insertCell(-1);
			td.className = "datepickheader";
			td.appendChild(document.createTextNode("M"));
			td = tr.insertCell(-1);
			td.className = "datepickheader";
			td.appendChild(document.createTextNode("T"));
			td = tr.insertCell(-1);
			td.className = "datepickheader";
			td.appendChild(document.createTextNode("O"));
			td = tr.insertCell(-1);
			td.className = "datepickheader";
			td.appendChild(document.createTextNode("T"));
			td = tr.insertCell(-1);
			td.className = "datepickheader";
			td.appendChild(document.createTextNode("F"));
			td = tr.insertCell(-1);
			td.className = "datepickheader";
			td.appendChild(document.createTextNode("L"));
			td = tr.insertCell(-1);
			td.className = "datepickheader";
			td.appendChild(document.createTextNode("S"));			
			this.div.appendChild(table);
			var tr = null;
			// render table
			var offset = new Array(-5, 1, 0, -1, -2, -3, -4);
			var daysInMonth = 32 - new Date(this.startDate.getFullYear(), this.startDate.getMonth(), 32).getDate();
			var startDay = offset[this.startDate.getDay()];
			var endDay = daysInMonth + (8 - new Date(this.startDate.getFullYear(), this.startDate.getMonth(), daysInMonth).getDay());
			var tr = null;
			var date = new Date(this.startDate);
			var dc = 0;                     
			var today = new Date();
			for(var i=startDay;i<endDay;i++)
			{
				date = new Date(this.startDate.getFullYear(),this.startDate.getMonth(),i);
				if(dc%7==0)
				{
					tr = table.insertRow(-1);
					var td = tr.insertCell(-1);	
					var link = document.createElement("a");
					link.datePicker = this;
					link.date = new Date(date);
					link.href = "javascript:void(0)";
					link.appendChild(document.createTextNode(date.getWeek()));
					link.className = "datepickweekselect";
					link.onclick = this.handleWeekCallback;
					td.appendChild(link);
					td.className = "datepickweekhead";
				}	
				var td = tr.insertCell(-1);
				var link = document.createElement("a");
				link.appendChild(document.createTextNode(date.getDate()));				
				link.href = "javascript:void(0)";
				link.date = new Date(date);
				link.datePicker = this;
				link.onclick = this.handleCallback;
				link.className = (i<1||i>daysInMonth)?"datepickdayd":"datepickday";
				if(link.date.getDate()==today.getDate() && link.date.getMonth()==today.getMonth() && link.date.getFullYear()==today.getFullYear())
					link.className = link.className = " today";
				td.appendChild(link);
				dc++;
			}			
			tr = table.insertRow(-1);
			td = tr.insertCell(-1);
			td.className = "datepickfoot";
			var link = document.createElement("a");
			link.appendChild(document.createTextNode("<"));
			link.href = "javascript:void(0)";
			link.datePicker = this;
			link.className = "datepickprev";
			link.onclick = function()
			{
			 	this.datePicker.startDate.setMonth(this.datePicker.startDate.getMonth()-1);
			 	this.datePicker.Render();
			}
			td.appendChild(link);			
			td = tr.insertCell(-1);
			td.className = "datepickfoot";
			td.colSpan = 6;
			td.appendChild(document.createTextNode(this.months[this.startDate.getMonth()] + " - " + this.startDate.getFullYear()));
			td = tr.insertCell(-1);
			td.className = "datepickfoot";
			var link = document.createElement("a");
			link.href = "javascript:void(0)";
			link.datePicker = this;
			link.className = "datepicknext";
			link.onclick = function()
			{
			 	this.datePicker.startDate.setMonth(this.datePicker.startDate.getMonth()+1);
			 	this.datePicker.Render();
			}
			link.appendChild(document.createTextNode(">"));
			td.appendChild(link);
		}
		,
		handleCallback : function()
		{
			this.datePicker.callback(this.date,false);
		}
		,
		handleWeekCallback : function()
		{
			this.datePicker.callback(this.date,true);
		}
		,
		Close : function()
		{
		 	document.body.removeChild(this.div);
		}
	}
	
	/**
	 * returns the absolute Y position of the object
	 **/
	function findPosY(obj)
	{
		var curtop = 0;
		if (obj.offsetParent)
		{
			while (obj.offsetParent)
			{
				var xy = 0;
				curtop += obj.offsetTop + xy;
				obj = obj.offsetParent;
			}
		}
		else if (obj.y)
			curtop += obj.y;
		return curtop;
	}

	/**
	 * returns the absolute X position of the object
	 **/
	function findPosX(obj)
	{
		var curleft = 0;
		if (obj.offsetParent)
		{
			while (obj.offsetParent)
			{
				curleft += obj.offsetLeft;
				obj = obj.offsetParent;
			}
		}
		else if (obj.x)
			curleft += obj.x;
		return curleft;
	}