<script language = "Javascript">
// Declaring valid date character, minimum year and maximum year
var dtCh= "/";
//var minYear=1900;
//var maxYear=2100;

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 strMonth=dtStr.substring(0,pos1)
	var strDay=dtStr.substring(pos1+1,pos2)
	var strYear=dtStr.substring(pos2+1)
	strYr=strYear	
	if (dtStr != '//'){
		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)
		}
		month=parseInt(strMonth)
		day=parseInt(strDay)
		year=parseInt(strYr)
		if (pos1==-1 || pos2==-1){
			//alert("The date format should be : mm/dd/yyyy")
			return false
		}
		if (month<1 || month>12 || isNaN(month)){
			//alert("Please enter a valid month")
			return false
		}
		if (isNaN(day) || day<1 || day>31 || (month==2 && day>daysInFebruary(year)) || day > daysInMonth[month]){
			//alert("Please enter a valid day")
			return false
		}
		//if (strYear.length != 4 || year==0 || year<minYear || year>maxYear){
		if (strYear.length != 4 || year==0){
			//alert("Please enter a valid 4 digit year")
			return false
		}
		if (dtStr.indexOf(dtCh,pos2+1)!=-1 || isInteger(stripCharsInBag(dtStr, dtCh))==false){
			//alert("Please enter a valid date")
			return false
		}
	}
	return true
}

function isTime(tmStr){	
	var tmCh = ':';
	var pos=tmStr.indexOf(tmCh)	
	var strHour=tmStr.substring(0,pos)
	var strMinute=tmStr.substring(pos+1)		
	if (tmStr != ''){		
		if (strHour.charAt(0)=="0" && strHour.length>1) strHour=strHour.substring(1)
		if (strMinute.charAt(0)=="0" && strMinute.length>1) strMinute=strMinute.substring(1)		
		intHour = parseInt(strHour);		
		intMinute = parseInt(strMinute);		
		if (pos==-1){
			//alert("The time format should be : hh:mm")
			return false
		}
		if (intHour<0 || intHour>24 || isNaN(intHour)){
			//alert("Please enter a valid hour! " + tmStr)
			return false
		}
		if (isNaN(intMinute) || intMinute<0 || intMinute>59){
			//alert("Please enter a valid minute! " + + tmStr)
			return false
		}
		if (intHour==24 && intMinute>0) {
			//alert("Please enter a valid time! " + + tmStr)
			return false
		}
		if (tmStr.indexOf(tmCh,pos+1)!=-1 || isInteger(stripCharsInBag(tmStr, tmCh))==false){
			//alert("Please enter a valid time! " + + tmStr )
			return false
		}
	}
	return true
}

function isValidDay(day,optional){
	if (day) {
		if (isNaN(day)) {
			return false;
		}
		else if (day<1 || day>31) {
			return false;
		}	
	}
	else if (!optional) {
		return false;
	}
	return true
}

function isValidYear(year,optional){
	if (year) {
		if (isNaN(year)) {
			//alert("isNaN")
			return false;
		}
		else if (year<1900 || year>2100) {
			//alert("1900 <= Year <= 2100")
			return false;
		}	
	}
	else if (!optional) {
	  //alert("Not optional")
		return false;
	}
	return true
}

function isValiddate(day,month,year,optional) {
	if (isValidDay(day,optional)==false) {
		alert('Voer een geldige datum in! (dag)');
		return false
	}
	else if (isValidYear(year,optional)==false) {
		alert('Voer een geldige datum in! (jaar)');
		return false
	}
	else if(isDate(month + '/' + day + '/' + year)==false){
		alert('Voer een geldige datum in!');
		return false
	}	
	return true
}

function isValidTime(hour,minute,optional){
	if (hour && minute) {
		if(isTime(hour + ':' + minute)==false){
			alert('Voer een geldige tijd in!');
			return false
		}
	}
	else if (hour || minute) {
		alert('Voer een geldige tijd in!');
		return false
	}
	else if(!optional){
		alert('Voer een tijd in!');		
	  return false
	}  
	return true
}

function isValidDateTime(dag,uur){
	if ((dag && (!uur)) || ((!dag) && uur)){
		alert('Voer zowel datum als tijd in!');
		return false
	}
	else 
		return true
}

function isValidDatePeriod(dag_start,maand_start,jaar_start,dag_eind,maand_eind,jaar_eind){
	if (dag_start && dag_eind)
		if (parseInt(jaar_eind)>parseInt(jaar_start))
			return true
		else
			if (parseInt(jaar_eind)==parseInt(jaar_start))
				if (parseInt(maand_eind)>parseInt(maand_start))
					return true
				else
					return (parseInt(maand_eind)==parseInt(maand_start) && parseInt(dag_eind)>=parseInt(dag_start))	
			else
				return false	
	else
		return true	
}

function isValidDateTimePeriod(dag_start,maand_start,jaar_start,uur_start,minuut_start,dag_eind,maand_eind,jaar_eind,uur_eind,minuut_eind){	
	if (dag_start && dag_eind)
		if (parseInt(jaar_eind)>parseInt(jaar_start))
			return true
		else
			if (parseInt(jaar_eind)==parseInt(jaar_start))
				if (parseInt(maand_eind)>parseInt(maand_start))
					return true
				else
					if (parseInt(maand_eind)==parseInt(maand_start)) 
						if (parseInt(dag_eind)>parseInt(dag_start))	
							return true
						else
							if (parseInt(dag_eind)==parseInt(dag_start))	
								if (parseInt(uur_eind)>parseInt(uur_start))
									return true
								else
									return (parseInt(uur_eind)==parseInt(uur_start) && parseInt(minuut_eind)>=parseInt(minuut_start))
							else
								return false
					else
						return false					
			else
				return false	
	else
		return true	
}
</script>