function show_calendar2(str_target, str_datetime) {
	
	var arr_months = ["January", "February", "March", "April", "May", "June",
		"July", "August", "September", "October", "November", "December"];
	var week_days = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];
	var n_weekstart = 1; // day week starts from (normally 0 or 1)

	var dt_datetime = (str_datetime == null || str_datetime =="" ?  new Date() : str2dt2(str_datetime));
	var dt_prev_month = new Date(dt_datetime);
	dt_prev_month.setMonth(dt_datetime.getMonth()-1);
	if (dt_datetime.getMonth()%12 != (dt_prev_month.getMonth()+1)%12) {
		dt_prev_month.setMonth(dt_datetime.getMonth());
		dt_prev_month.setDate(0);
	}
	var dt_next_month = new Date(dt_datetime);
	dt_next_month.setMonth(dt_datetime.getMonth()+1);
	if ((dt_datetime.getMonth() + 1)%12 != dt_next_month.getMonth()%12)
		dt_next_month.setDate(0);
	
	var dt_firstday = new Date(dt_datetime);
	dt_firstday.setDate(1);
	dt_firstday.setDate(1-(7+dt_firstday.getDay()-n_weekstart)%7);
	var dt_lastday = new Date(dt_next_month);
	dt_lastday.setDate(0);
	
	// html generation 
	// print calendar header
	var str_buffer = new String (
		"<html>\n"+
		"	<head>\n"+
		"		<title>Calendar</title>\n"+
		"		<LINK REL=\"STYLESHEET\" HREF=\"CallenderStyle.css\" TYPE=\"text/css\">\n"+
		"	</head>\n"+
		"<body>\n"+
		"	<table cellspacing=\"0\" border=\"0\" width=\"100%\">\n"+
		"	<tr>\n"+
		"		<td>\n"+
		"			<table class=\"TableGrid\" cellspacing=\"0\" cellpadding=\"3\" border=\"0\" width=\"100%\">\n"+
		"				<tr>\n"+
		"					<td CLASS=\"DateHeader\"><a href=\"javascript:window.opener.show_calendar2('"+str_target+"', '"+ dt2dtstr2(dt_prev_month)+"');\"><img src=\"http://www.basement-picasso.co.uk/new/images/Calprev.gif\" width=\"16\" height=\"16\" border=\"0\" alt=\"previous month\"></a></td>\n"+
		"					<td CLASS=\"DateHeader\" colspan=\"5\">"+arr_months[dt_datetime.getMonth()]+" "+dt_datetime.getFullYear()+"</td>\n"+
		"					<td CLASS=\"DateHeader\" align=\"right\"><a href=\"javascript:window.opener.show_calendar2('"+str_target+"', '"+dt2dtstr2(dt_next_month)+"');\"><img src=\"http://www.basement-picasso.co.uk/new/images/Calnext.gif\" width=\"16\" height=\"16\" border=\"0\" alt=\"next month\"></a></td>\n"+
		"				</tr>\n"
	);

	var dt_current_day = new Date(dt_firstday);
	
	// print weekdays titles
	str_buffer += "<tr>\n";
	for (var n=0; n<7; n++)
		str_buffer += "<td class=\"DaysHeader\">"+
			week_days[(n_weekstart+n)%7]+"</td>\n";
	

	// print calendar table
	str_buffer += "</tr>\n";



	// print dates
	while (dt_current_day.getMonth() == dt_datetime.getMonth() ||
		dt_current_day.getMonth() == dt_firstday.getMonth()) {
		
		// print row heder
		str_buffer += "<tr>\n";
		for (var n_current_wday=0; n_current_wday<7; n_current_wday++) {
				if ((dt_current_day.getDate() == dt_datetime.getDate()) && (dt_current_day.getMonth() == dt_datetime.getMonth()) && (dt_current_day.getMonth() == dt_datetime.getMonth()))
					// print current date
					str_buffer += "	<td CLASS=\"Today\"><a href=\"javascript:window.opener."+str_target+".value='"+dt2dtstr2(dt_current_day)+"'; window.close();\">"+"<DIV CLASS=\"Today\">"+ dt_current_day.getDate()+"</DIV></a></td>\n";
				
				else if ((dt_current_day.getDay() != 0 && dt_current_day.getDay() != 6) && (dt_current_day.getMonth() == dt_datetime.getMonth()))
					// print working days of current month
					str_buffer += "	<td CLASS=\"WeekDay\"><a href=\"javascript:window.opener."+str_target+".value='"+dt2dtstr2(dt_current_day)+"'; window.close();\">"+"<DIV CLASS=\"WeekDay\">"+ dt_current_day.getDate()+"</DIV></a></td>\n";
				
				else if ((dt_current_day.getDay() == 0 || dt_current_day.getDay() == 6 ) && (dt_current_day.getMonth() != dt_datetime.getMonth()))
					// weekend day not in current month
					str_buffer += "	<td CLASS=\"NextMonth\"><a href=\"javascript:window.opener."+str_target+".value='"+dt2dtstr2(dt_current_day)+"'; window.close();\">"+"<DIV CLASS=\"NextMonth\">"+ dt_current_day.getDate()+"</DIV></a></td>\n";	
				

				else if (dt_current_day.getDay() == 0 || dt_current_day.getDay() == 6 )
					// weekend days
					str_buffer += "	<td CLASS=\"WeekEnd\"><a href=\"javascript:window.opener."+str_target+".value='"+dt2dtstr2(dt_current_day)+"'; window.close();\">"+"<DIV CLASS=\"WeekEnd\">"+ dt_current_day.getDate()+"</DIV></a></td>\n";
				
				
				else 
					str_buffer += "	<td CLASS=\"NextMonth\"><a href=\"javascript:window.opener."+str_target+".value='"+dt2dtstr2(dt_current_day)+"'; window.close();\">"+"<DIV CLASS=\"NextMonth\">"+ dt_current_day.getDate()+"</DIV></a></td>\n";	

				dt_current_day.setDate(dt_current_day.getDate()+1);
		}
		// print row footer
		str_buffer += "</tr>\n";
	}
	// print calendar footer
	str_buffer +=
		"			</table>\n" +
		"		</tr>\n"+
		"	</td>\n"+
		"</table>\n" +
		"</body>\n" +
		"</html>\n";

	var vWinCal = window.open("", "Calendar", 
		"width=250,height=250,status=no,resizable=yes,top=200,left=200");
	vWinCal.opener = self;
	vWinCal.focus();
	var calc_doc = vWinCal.document;
	calc_doc.write (str_buffer);
	calc_doc.close();
}
// datetime parsing and formatting routimes. modify them if you wish other datetime format

function str2dt2 (str_datetime) {
//	var re_date = /^(\d+)\-(\d+)\-(\d+)$/;
	var re_date = /^(\d+)\/(\d+)\/(\d+)$/;
	if (!re_date.exec(str_datetime))
		return alert("Invalid Datetime format: "+ str_datetime  +" should be dd/mm/yyyy eg 31/12/1999");
	var Mon
	if ((RegExp.$2)=='Jan'){Mon='0';}
	if ((RegExp.$2)=='Feb'){Mon='1';}
	if ((RegExp.$2)=='Mar'){Mon='2';}
	if ((RegExp.$2)=='Apr'){Mon='3';}
	if ((RegExp.$2)=='May'){Mon='4';}
	if ((RegExp.$2)=='Jun'){Mon='5';}
	if ((RegExp.$2)=='Jul'){Mon='6';}
	if ((RegExp.$2)=='Aug'){Mon='7';}
	if ((RegExp.$2)=='Sep'){Mon='8';}
	if ((RegExp.$2)=='Oct'){Mon='9';}
	if ((RegExp.$2)=='Nov'){Mon='10';}
	if ((RegExp.$2)=='Dec'){Mon='11';}
	
//	return ();
	return (new Date (RegExp.$3,RegExp.$2-1, RegExp.$1));
}



function dt2dtstr2 (dt_datetime) {
	return (new String (
			//dt_datetime.getDate()+"-"+(dt_datetime.getMonth()+1)+"-"+dt_datetime.getFullYear()));
			dt_datetime.getDate()+"/"+(dt_datetime.getMonth()+1)+"/"+dt_datetime.getFullYear()));
}
//original function dt2dtstr2 (dt_datetime) {
//	return (new String (
//			//dt_datetime.getDate()+"-"+(dt_datetime.getMonth()+1)+"-"+dt_datetime.getFullYear()));
//			dt_datetime.getDate()+" "+MonthString((dt_datetime.getMonth()))+" "+dt_datetime.getFullYear()));
//}


// open popup window for date offset popup

function OpenWin(URL,name,height,width){
var vWinCal = window.open(URL, name, "width=" + width + ",height=" + height + ",status=no,resizable=yes,scrollbars=yes,top=100,left=100");
vWinCal.focus();
}

function MonthString (month){
var arr_months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun","Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];

return arr_months[month];

}




