var objTxtBoxTarget
var objLTDDate 
function show_calendar(str_target, str_datetime,divId2write) {
    
	objTxtBoxTarget = document.getElementById(str_target);
	
	var arr_months = ["Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"];
	var week_days = ["S","M","T","W","T","F","S"];
	var n_weekstart = 0; // day week starts from (normally 0 or 1)

	var dt_datetime = (str_datetime == null || str_datetime =="" ?  new Date() : str2dt(str_datetime));
	var dt_prev_month = new Date(dt_datetime);
	dt_prev_month.setMonth(dt_datetime.getMonth()-1);
	var dt_next_month = new Date(dt_datetime);
	dt_next_month.setMonth(dt_datetime.getMonth()+1);
	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 (feel free to tune it for your particular application)
	// print calendar header
	var str_buffer = new String (
		"<table cellspacing=\"0\" border=\"0\" width=\"100%\" >\n"+
		"<tr><td bgcolor=\"#353535\">\n"+
		"<table cellspacing=\"0\" cellpadding=\"3\" border=\"0\" width=\"100%\">\n"+
		"<tr>\n	<td><a href=\"javascript:show_calendar('"+
		str_target+"', '"+ dt2dtstr(dt_prev_month)+"'+document.cal.time.value,'"+divId2write+"');\">"+
		"<img src=\""+IMG_SERVER_URL+"double_arrow_left.gif\"  border=\"0\""+
		" alt=\"previous month\"></a></td>\n"+
		"	<td style=\"text-align:center;color:White;font-family:Arial; font-size:12px;\" colspan=\"5\">"+arr_months[dt_datetime.getMonth()]+" "+dt_datetime.getFullYear()+"</font></td>\n"+
		"	<td align=\"right\"><a href=\"javascript:show_calendar('"
		+str_target+"', '"+dt2dtstr(dt_next_month)+"'+document.cal.time.value,'"+divId2write+"');\">"+
		"<img src=\""+IMG_SERVER_URL+"double_arrow_right.gif\"  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  style=\"background-color:#CDCC34;color:Black; font-family:Arial; font-size:11px;\" align=\"center\">"+
		week_days[(n_weekstart+n)%7]+"</td>\n";
	// print calendar table
	str_buffer += "</tr>\n";
	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())
					// print current date
					str_buffer += "	<td style=\"text-align:center;border:solid 1px #CDCC34;\" >";
				else if (dt_current_day.getDay() == 6)
					// weekend days
					str_buffer += "	<td style=\"text-align:center;\">";
				else
					// print working days of current month
					str_buffer += "	<td style=\"text-align:center;\">";

				if (dt_current_day.getMonth() == dt_datetime.getMonth())
					// print days of current month
					str_buffer += "<a href=\"javascript:void(0);\" onclick=\"objTxtBoxTarget.value='"+dt2dtstr(dt_current_day)+"'+document.cal.time.value;changeCurrentDate(this); \" style=\"color:#CCCD34;font-size:12px;text-decoration:underline;\">"+
					"";
				else 
					// print days of other months
					str_buffer += "<a href=\"javascript:void(0);\" onclick=\"objTxtBoxTarget.value='"+dt2dtstr(dt_current_day)+"'+document.cal.time.value; \" style=\"text-align:center;color:gray;font-size:12px;text-decoration:line-through;\">"	;
				str_buffer += dt_current_day.getDate()+"</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></td></tr></table>"+
		"<form name=\"cal\"><input type=\"hidden\" name=\"time\" value=\""+dt2tmstr(dt_datetime)+
		"\" size=\"8\" maxlength=\"8\"></form>\n";
	var calObj = document.getElementById(divId2write);
	calObj.innerHTML=str_buffer;
	objTxtBoxTarget.value=dt2dtstr(new Date());
}
// datetime parsing and formatting routimes. modify them if you wish other datetime format
function str2dt (str_datetime) {
	var re_date = /^(\d+)\/(\d+)\/(\d+)$/;
	if (!re_date.exec(str_datetime)){
		return alert("Invalid Datetime format: "+ str_datetime);
	}
	return (new Date (RegExp.$3, RegExp.$2-1, RegExp.$1));
}
function dt2dtstr (dt_datetime) {
	return (new String (dt_datetime.getDate()+"/"+(dt_datetime.getMonth()+1)+"/"+dt_datetime.getFullYear()));
}
function dt2tmstr (dt_datetime) {
	return ""
}
function changeCurrentDate(objTD){
    if (objLTDDate){
       objLTDDate.style.color='#CDCC34'; 
       objLTDDate.style.backgroundColor='Transparent';
    }
    objTD.style.color='black';
    objTD.style.backgroundColor='#CDCC34';
    objLTDDate=objTD;
}