// Title: Timestamp picker
// Description: See the demo at url
// URL: http://us.geocities.com/tspicker/
// Script featured on: http://javascriptkit.com/script/script2/timestamp.shtml
// Version: 1.0
// Date: 12-05-2001 (mm-dd-yyyy)
// Author: Denis Gritcyuk <denis@softcomplex.com>; <tspicker@yahoo.com>
// Notes: Permission given to use this script in any kind of applications if
//    header lines are left unchanged. Feel free to contact the author
//    for feature requests and/or donations

function show_calendar(str_target, str_datetime) {
	var arr_months = ["January", "February", "March", "April", "May", "June",
		"July", "August", "September", "October", "November", "December"];
	var week_days = ["Su", "Mo", "Tu", "We", "Th", "Fr", "Sa"];
	var n_weekstart = 1; // 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 (
		"<html>\n"+
		"<head>\n"+
		"	<title>Calendar</title>\n"+
		"	<style type=\"text/css\">\n"+
		"		body { font-family: Arial, Verdana, sans-serif; margin: 5px; }\n"+
		"		span { font-size: 10px; color: #666666; }\n"+
		"		td { padding: 2px; border: 2px solid #FFFFFF; }\n"+
		"		a { font-size: 10px; color: #666666; }\n"+
		"		.monthText { font-size: 14px; font-weight: bold; color: #666666; }\n"+
		"		.dayCell { width: 29px; height: 15px; }\n"+
		"	</style>\n"+
		"</head>\n"+
		"<body bgcolor=\"#FFFFFF\">\n"+
		"<table width=\"225\" cellspacing=\"0\" cellpadding=\"0\" border=\"0\" align=\"center\">\n"+
		"<tr>\n"+
		"<td colspan=\"2\" align=\"left\"><a href=\"javascript:window.opener.show_calendar('"+str_target+"', '"+ dt2dtstr(dt_prev_month)+"');\">&laquo;&nbsp;Prev</a></td>\n"+
		"<td colspan=\"3\" align=\"center\"><span class=\"monthText\">"+arr_months[dt_datetime.getMonth()]+" "+dt_datetime.getFullYear()+"</span></td>\n"+
		"<td colspan=\"2\" align=\"right\"><a href=\"javascript:window.opener.show_calendar('"+str_target+"', '"+dt2dtstr(dt_next_month)+"');\">Next&nbsp;&raquo;</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=\"dayCell\" bgcolor=\"#C4C473\" align=\"center\">"+
		"<span><strong>"+
		week_days[(n_weekstart+n)%7]+"</strong></span></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 class=\"dayCell\" bgcolor=\"#FFFFFF\" align=\"center\"><a href=\"javascript:window.opener."+str_target+".value='"+dt2dtstr(dt_current_day)+"'; window.close();\">"+dt_current_day.getDate()+"</a></td>\n";
				else if (dt_current_day.getDate() != dt_datetime.getDate() && dt_current_day.getMonth() == dt_datetime.getMonth())
					// print days of current month
					str_buffer += "	<td class=\"dayCell\" bgcolor=\"#E1E1B9\" align=\"center\"><a href=\"javascript:window.opener."+str_target+".value='"+dt2dtstr(dt_current_day)+"'; window.close();\">"+dt_current_day.getDate()+"</a></td>\n";
				else
					// print working days of current month
					str_buffer += "	<td class=\"dayCell\" bgcolor=\"#E1E1B9\" align=\"center\"><span>&nbsp;</span></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" +
		"</body>\n" +
		"</html>\n";

	var vWinCal = window.open("", "Calendar", 
		"width=275,height=225,status=no,resizable=yes,top=200,left=200");
	vWinCal.opener = self;
	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 str2dt (str_datetime) {
	var re_date = /^(\d+)\/(\d+)\/(\d+)\s*$/;
	if (!re_date.exec(str_datetime))
		return alert("Invalid Datetime format: "+ str_datetime);
	return (new Date (RegExp.$3, RegExp.$1-1, RegExp.$2));	
}
function dt2dtstr (dt_datetime) {
	return (new String (
			(dt_datetime.getMonth()+1)+"/"+dt_datetime.getDate()+"/"+dt_datetime.getFullYear()));
}
function dt2tmstr (dt_datetime) {
	return (new String (
			dt_datetime.getHours()+":"+dt_datetime.getMinutes()+":"+dt_datetime.getSeconds()));
}


