Calendar._MN is undefined magento

Today i was implementing caledar feature in frontend. I have included all the required js and css file for that.

<link rel="stylesheet" type="text/css" href="http://www.beds.sg/v2/js/calendar/calendar-win2k-1.css" />

<script type="text/javascript" src="http://www.beds.sg/v2/js/calendar/calendar.js"></script>

<script type="text/javascript" src="http://www.beds.sg/v2/js/calendar/calendar-setup.js"></script>

Still it was showing this error."Calendar._MN is undefined"
After some R&D i found out that i missed to include some javascript that is necessary for calendar to work.
I just included following lined on the page and it begins to work smoothly.

<script type="text/javascript">

//<![CDATA[

enUS = {"m":{"wide":["January","February","March","April","May","June","July","August","September","October","November","December"],"abbr":["Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"]}}; // en_US locale reference

Calendar._DN = ["Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"]; // full day names

Calendar._SDN = ["Sun","Mon","Tue","Wed","Thu","Fri","Sat"]; // short day names

Calendar._FD = 0; // First day of the week. "0" means display Sunday first, "1" means display Monday first, etc.

Calendar._MN = ["January","February","March","April","May","June","July","August","September","October","November","December"]; // full month names

Calendar._SMN = ["Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"]; // short month names

Calendar._am = "AM"; // am/pm

Calendar._pm = "PM";

// tooltips

Calendar._TT = {};

Calendar._TT["INFO"] = "About the calendar";

Calendar._TT["ABOUT"] =

"DHTML Date/Time Selector\n" +

"(c) dynarch.com 2002-2005 / Author: Mihai Bazon\n" +

"For latest version visit: http://www.dynarch.com/projects/calendar/\n" +

"Distributed under GNU LGPL. See http://gnu.org/licenses/lgpl.html for details." +

"\n\n" +

"Date selection:\n" +

"- Use the \xab, \xbb buttons to select year\n" +

"- Use the " + String.fromCharCode(0x2039) + ", " + String.fromCharCode(0x203a) + " buttons to select month\n" +

"- Hold mouse button on any of the above buttons for faster selection.";

Calendar._TT["ABOUT_TIME"] = "\n\n" +

"Time selection:\n" +

"- Click on any of the time parts to increase it\n" +

"- or Shift-click to decrease it\n" +

"- or click and drag for faster selection.";

Calendar._TT["PREV_YEAR"] = "Prev. year (hold for menu)";

Calendar._TT["PREV_MONTH"] = "Prev. month (hold for menu)";

Calendar._TT["GO_TODAY"] = "Go Today";

Calendar._TT["NEXT_MONTH"] = "Next month (hold for menu)";

Calendar._TT["NEXT_YEAR"] = "Next year (hold for menu)";

Calendar._TT["SEL_DATE"] = "Select date";

Calendar._TT["DRAG_TO_MOVE"] = "Drag to move";

Calendar._TT["PART_TODAY"] = ' (' + "Today" + ')';

// the following is to inform that "%s" is to be the first day of week

Calendar._TT["DAY_FIRST"] = "Display %s first";

// This may be locale-dependent. It specifies the week-end days, as an array

// of comma-separated numbers. The numbers are from 0 to 6: 0 means Sunday, 1

// means Monday, etc.

Calendar._TT["WEEKEND"] = "0,6";

Calendar._TT["CLOSE"] = "Close";

Calendar._TT["TODAY"] = "Today";

Calendar._TT["TIME_PART"] = "(Shift-)Click or drag to change value";

// date formats

Calendar._TT["DEF_DATE_FORMAT"] = "%b %e, %Y";

Calendar._TT["TT_DATE_FORMAT"] = "%B %e, %Y";

Calendar._TT["WK"] = "Week";

Calendar._TT["TIME"] = "Time:";

CalendarDateObject._LOCAL_TIMZEONE_OFFSET_SECONDS = -28800;

CalendarDateObject._SERVER_TIMZEONE_SECONDS = 1333496531;

//]]>

</script>