function GetLastDayMonth(VarMonth,VarYear)
{
	var TextPrivate = ""
	ActualDay = 27
	EndOfMonth = false

	while(!EndOfMonth)
	{
		ActualDay++ 
		Datum = new Date(VarYear,VarMonth,ActualDay)
		if(Datum.getMonth()!=VarMonth)
		EndOfMonth = true
	}
	
	return --ActualDay
}

// Prefix = formName.fieldPrefix
function CheckNumberDays(Prefix)
{
	NumDays = eval('GetLastDayMonth(document.'+Prefix+'_MONTH.value-1,document.'+Prefix+'_YEAR.value)')
	if(eval('document.'+Prefix+'_DAY.options.length') != NumDays)
	{
		SelectedValue = eval('document.'+Prefix+'_DAY.options[document.'+Prefix+'_DAY.options.selectedIndex].value')
		eval('document.'+Prefix+'_DAY.options.length = 28')
		for (var i=29; i<=NumDays; i++)
		{
			eval('document.'+Prefix+'_DAY.options[i-1] = new Option(GetDayStr(i), i)')   
		}
		if(SelectedValue*1>=NumDays*1) 
		{
			eval('document.'+Prefix+'_DAY.value = '+NumDays)
		}
		else
			eval('document.'+Prefix+'_DAY.value = '+SelectedValue)
	}
}

function GetDayStr(i)
{
	var TextPrivate = i + " "
	StrDt = 'th'
	if((i==1)||(i==21)||(i==31))
		StrDt = 'st'
	if((i==2)||(i==22))
		StrDt = 'nd'
	if((i==3)||(i==23))
		StrDt = 'rd'
	return TextPrivate + StrDt
}