function calculateDate(value)
{
	if (document.form.fromDate.value != null && value != null)
	{
		var date = getDate(document.form.fromDate.value);
	  	date.setDate(date.getDate() + parseInt(value)-1);
		
		
		var curr_date = date.getDate();
 		var curr_month = date.getMonth()+1;
		var curr_year = date.getFullYear();
		
		var dateString = formatString(curr_date) + "-" + formatString(curr_month) + "-" + curr_year;
		document.form.toDate.value= dateString;
 	}
}
                                                                                 
function calculateValidDays()
{
	if (document.form.fromDate.value != null && document.form.toDate.value != null)
	{
		var fromDate = getDate(document.form.fromDate.value);
		var toDate = getDate(document.form.toDate.value);
		var date = new Date();
		date.setTime(Math.abs(fromDate.getTime() - toDate.getTime()));
	 	 
		days = Math.floor(date.getTime() / (1000 * 60 * 60 * 24)); 
	 
		document.form.days.value= days+1;
	}
	else if(document.form.toDate.value != null && document.form.days.value != "")
	{
		var date = getDate(document.form.toDate.value);
		date.setDate(date.getDate() - parseInt(document.form.days.value));
		
		var curr_date = date.getDate();
 		var curr_month = date.getMonth()+1;
		var curr_year = date.getFullYear();
		
		var dateString = formatString(curr_date) + "-" + formatString(curr_month) + "-" + curr_year;
		document.form.fromDate.value= dateString;
	}
	else if(document.form.fromDate.value != null && document.form.days.value != "")
	{
		var date = getDate(document.form.fromDate.value);
		date.setDate(date.getDate() + parseInt(document.form.days.value)+1);
		var curr_date = date.getDate();
 		var curr_month = date.getMonth()+1;
		var curr_year = date.getFullYear();
		
		var dateString = formatString(curr_date) + "-" + formatString(curr_month) + "-" + curr_year;
		document.form.toDate.value= dateString;
	}
}

function formatString(value)
{
	return ("00" + value).substring(("00" + value).length-2, ("00" + value).length);
}

function getDate(dateValue)
{
	var m_arrDate = dateValue.split("-");
	var m_DAY = m_arrDate[0];
	var m_MONTH = m_arrDate[1]-1;
	var m_YEAR = m_arrDate[2];

	if(m_YEAR.length > 4)
	{
		return new Date();
	}

	return new Date(m_YEAR, m_MONTH, m_DAY);
}

function reloadPeriod()
{
	document.form.action = "annual_leave_application_form.php?from="+document.form.fromDate.value+"&to="+document.form.toDate.value+"&reason="+document.form.reason.value;
	document.form.submit();
}

var dtCh= "-";
var minYear=1900;
var maxYear=2200;

function isInteger(s){
	var i;
    for (i = 0; i < s.length; i++){   
        // Check that current character is number.
        var c = s.charAt(i);
        if (((c < "0") || (c > "9"))) return false;
    }
    // All characters are numbers.
    return true;
}

function stripCharsInBag(s, bag){
	var i;
    var returnString = "";
    // Search through string's characters one by one.
    // If character is not in bag, append to returnString.
    for (i = 0; i < s.length; i++){   
        var c = s.charAt(i);
        if (bag.indexOf(c) == -1) returnString += c;
    }
    return returnString;
}

function daysInFebruary (year){
	// February has 29 days in any year evenly divisible by four,
    // EXCEPT for centurial years which are not also divisible by 400.
    return (((year % 4 == 0) && ( (!(year % 100 == 0)) || (year % 400 == 0))) ? 29 : 28 );
}
function DaysArray(n) {
	for (var i = 1; i <= n; i++) {
		this[i] = 31;
		if (i==4 || i==6 || i==9 || i==11) {this[i] = 30;}
		if (i==2) {this[i] = 29;}
   } 
   return this;
}

function isDate(dtStr){
	var daysInMonth = DaysArray(12);
	var pos1=dtStr.indexOf(dtCh);
	var pos2=dtStr.indexOf(dtCh,pos1+1); 
	var strDay=dtStr.substring(0,pos1);
	var strMonth=dtStr.substring(pos1+1,pos2);
	var strYear =dtStr.substring(pos2+1);
	strYr=strYear;
	if (strDay.charAt(0)=="0" && strDay.length>1) strDay=strDay.substring(1)
	if (strMonth.charAt(0)=="0" && strMonth.length>1) strMonth=strMonth.substring(1)
	for (var i = 1; i <= 3; i++) {
		if (strYr.charAt(0)=="0" && strYr.length>1) strYr=strYr.substring(1);
	}
	year=parseInt(strYr);
	month=parseInt(strMonth);
	day=parseInt(strDay);
	
	if (pos1==-1 || pos2==-1){
		alert("1Please insert valid date in the format :dd-mm-YYYY (eg: 01-01-2009).");
		return false;
	}
	if (strMonth.length<1 || month<1 || month>12){
		alert("2Please insert valid date in the format :dd-mm-YYYY (eg: 01-01-2009).");
		return false;
	}
	if (strDay.length<1 || day<1 || day>31 || (month==2 && day>daysInFebruary(year)) || day > daysInMonth[month]){
		alert("3Please insert valid date in the format :dd-mm-YYYY (eg: 01-01-2009).");
		return false;
	}
	if (strYear.length != 4 || year==0 || year<minYear || year>maxYear){
		alert("Please insert valid date in the format :dd-mm-YYYY (eg: 01-01-2009).");
		return false;
	}
	if (dtStr.indexOf(dtCh,pos2+1)!=-1 || isInteger(stripCharsInBag(dtStr, dtCh))==false){
		alert("4Please insert valid date in the format :dd-mm-YYYY (eg: 01-01-2009).");
		return false;
	}
return true;
}

function check_form(){						
				  	
					var dt_fromDate=document.form.fromDate;
					var dt_toDate=document.form.toDate;
					
					var strFromDate = form.fromDate.value;
					var dayPartFromDate = parseInt(strFromDate.substring(0,2),10);
					var monPartFromDate = parseInt(strFromDate.substring(3,5),10);
					var yearPartFromDate = parseInt(strFromDate.substring(6,10),10);
					var dtFrom = new Date(yearPartFromDate, monPartFromDate-1, dayPartFromDate);

					var strToDate = form.toDate.value;
					var dayPartToDate = parseInt(strToDate.substring(0,2),10);
					var monPartToDate = parseInt(strToDate.substring(3,5),10);
					var yearPartToDate = parseInt(strToDate.substring(6,10),10);
					var dtTo = new Date(yearPartToDate, monPartToDate-1, dayPartToDate);

					
					if ( form.fromDate.value == "")
					{
						alert("Please fill in all the fields marked with *");
						document.form.fromDate.focus();
						return false;
					}
					else if ( form.toDate.value == "")
					{
						alert("Please fill in all the fields marked with *");
						document.form.toDate.focus();
						return false;
					}
					
					else if (isDate(dt_fromDate.value)==false){
					dt_fromDate.focus();
					return false;
					}
					
    				else if (isDate(dt_toDate.value)==false){
					dt_toDate.focus();
					return false;
					}
					else if(dtTo < dtFrom){
					alert("Invalid date range. 'To' date should not be earlier than 'From' date");
					return false;
					}
					
				  return true;
				  }

a) which language ?
b) why the hell haven't you used code tags?
c) You have neither stated what it SHOULD do, or what it DOES do - how can we "fix it".
d) I hope a mod moves this to a proper forum so I can give you a proper de-rep for this crap.

Macromedia Dreamweaver MXSoftware(PHP) + Javascript + MySQL.
it is about the function to calculate a service length to a eleave system . the problem is i cannot find where is the mistake(which line) and the calculation is the day that have been calculate is more extra than needed.