Will someone help with Popup Calendar scripting

Please help, the popup calendar below was added to my website form and now the form will not work. Need to know the cause.

Thanks for the help,

<script language="JavaScript">
<!--
var months = new Array("January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December");
var daysInMonth = new Array(31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);
var days = new Array("S", "M", "T", "W", "T", "F", "S");

today = new getToday();
var element_id;

function getDays(month, year)
{
// Test for leap year when February is selected.
if (1 == month)
return ((0 == year % 4) && (0 != (year % 100))) ||
(0 == year % 400) ? 29 : 28;
else
return daysInMonth[month];
}

function getToday()
{
// Generate today's date.
this.now = new Date();
this.year = this.now.getFullYear() ; // Returned year XXXX
this.month = this.now.getMonth();
this.day = this.now.getDate();
}


function newCalendar()
{
var parseYear = parseInt(document.all.year [document.all.year.selectedIndex].text);

var newCal = new Date(parseYear , document.all.month.selectedIndex, 1);
var day = -1;
var startDay = newCal.getDay();
var daily = 0;

today = new getToday(); // 1st call
if ((today.year == newCal.getFullYear() ) && (today.month == newCal.getMonth()))
day = today.day;
// Cache the calendar table's tBody section, dayList.
var tableCal = document.all.calendar.tBodies.dayList;

var intDaysInMonth =
getDays(newCal.getMonth(), newCal.getFullYear() );

for (var intWeek = 0; intWeek < tableCal.rows.length; intWeek++)
for (var intDay = 0;
intDay < tableCal.rows[intWeek].cells.length;
intDay++)
{
var cell = tableCal.rows[intWeek].cells[intDay];

// Start counting days.
if ((intDay == startDay) && (0 == daily))
daily = 1;

// Highlight the current day.
cell.style.color = (day == daily) ? "red" : "";
if(day == daily)
{
document.all.todayday.innerText= "Today: " + day + "/" +
(newCal.getMonth()+1) + "/" + newCal.getFullYear() ;
}
// Output the day number into the cell.
if ((daily > 0) && (daily <= intDaysInMonth))
cell.innerText = daily++;
else
cell.innerText = "";
}

}

function getTodayDay()
{
document.all[element_id].value = today.day + "/" + (today.month+1) +
"/" + today.year;
//document.all.calendar.style.visibility="hidden";
document.all.calendar.style.display="none";
document.all.year.selectedIndex =100;
document.all.month.selectedIndex = today.month;
}

function getDate()
{
// This code executes when the user clicks on a day
// in the calendar.
if ("TD" == event.srcElement.tagName)
// Test whether day is valid.
if ("" != event.srcElement.innerText)
{
var mn = document.all.month.selectedIndex+1;
var Year = document.all.year [document.all.year.selectedIndex].text;
document.all[element_id].value=event.srcElement.innerText+"/"+mn +"/" +Year;
//document.all.calendar.style.visibility="hidden";
document.all.calendar.style.display="none";
}
}

function GetBodyOffsetX(el_name, shift)
{
var x;
var y;
x = 0;
y = 0;

var elem = document.all[el_name];
do
{
x += elem.offsetLeft;
y += elem.offsetTop;
if (elem.tagName == "BODY")
break;
elem = elem.offsetParent;
} while (1 > 0);

shift[0] = x;
shift[1] = y;
return x;
}

function SetCalendarOnElement(el_name)
{
if (el_name=="")
el_name = element_id;
var shift = new Array(2);
GetBodyOffsetX(el_name, shift);
document.all.calendar.style.pixelLeft = shift[0]; // - document.all.calendar.offsetLeft;
document.all.calendar.style.pixelTop = shift[1] + 25 ;
}



function ShowCalendar(elem_name)
{
if (elem_name=="")
elem_name = element_id;

element_id = elem_name; // element_id is global variable
newCalendar();
SetCalendarOnElement(element_id);
//document.all.calendar.style.visibility = "visible";
document.all.calendar.style.display="inline";
}

function HideCalendar()
{
//document.all.calendar.style.visibility="hidden";
document.all.calendar.style.display="none";
}

function toggleCalendar(elem_name)
{
//if (document.all.calendar.style.visibility == "hidden")
if(document.all.calendar.style.display=="none")
ShowCalendar(elem_name);
else
HideCalendar();
}
-->
</script>

<style>
.today {COLOR: black; FONT-FAMILY: sans-serif; FONT-SIZE: 10pt; FONT-WEIGHT: bold}
.days {COLOR: navy; FONT-FAMILY: sans-serif; FONT-SIZE: 10pt; FONT-WEIGHT: bold; TEXT-ALIGN: center}
.dates {COLOR: black; FONT-FAMILY: sans-serif; FONT-SIZE: 10pt}
</style>



<FORM name=myForm>
<INPUT id=MyDate name=MyDate size=15>
<a href="javascript:;" onClick="toggleCalendar('MyDate')">Calendar</a>
</form>











<TABLE bgColor=#ffffff border=1 cellPadding=0 cellSpacing=3 id=calendar style="DISPLAY: none; POSITION: absolute; Z-INDEX: 4">
<TBODY>
<TR>
<TD colSpan=7 vAlign=center>
<!-- Month combo box -->
<SELECT id=month onchange=newCalendar()>
<SCRIPT language=JavaScript>
// Output months into the document.
// Select current month.
for (var intLoop = 0; intLoop < months.length; intLoop++)
document.write("<OPTION " + (today.month == intLoop ? "Selected" : "") + ">" + months[intLoop]);
</SCRIPT>
</SELECT>
<!-- Year combo box -->
<SELECT id=year onchange=newCalendar()>
<SCRIPT language=JavaScript>
// Output years into the document.
// Select current year.
for (var intLoop = 2008; intLoop < 2011; intLoop++)
document.write("<OPTION " + (today.year == intLoop ? "Selected" : "") + ">" + intLoop);
</SCRIPT>
</SELECT>

</TD>
</TR>



<TR class=days>
<!-- Generate column for each day. -->
<SCRIPT language=JavaScript>
// Output days.
for (var intLoop = 0; intLoop < days.length; intLoop++)
document.write("<TD>" + days[intLoop] + "</TD>");
</SCRIPT>
</TR>


<TBODY class=dates id=dayList onclick="getDate('')" vAlign=center>
<!-- Generate grid for individual days. -->
<SCRIPT language=JavaScript>
for (var intWeeks = 0; intWeeks < 6; intWeeks++)
{
document.write("<TR>");
for (var intDays = 0; intDays < days.length; intDays++)
document.write("<TD></TD>");
document.write("</TR>");
}
</SCRIPT>

<!-- Generate today day. --></TBODY>
<TBODY>
<TR>
<TD class=today colSpan=5 id=todayday onclick=getTodayDay()></TD>
<TD align=right colSpan=2><A href="javascript:HideCalendar();"><SPAN style="COLOR: black; FONT-SIZE: 10px"><B>Hide</B></SPAN></A></TD>
</TR>
</TBODY>

</TABLE>

inthedark