var dtCh= "/";
var minYear=1900;
var maxYear=2100;
var errormessage="The following problems were found on the booking form:\n\n";

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

function reformDate(oldDate){
	var dateAr = oldDate.split('/');
	return dateAr[1] + '/' + dateAr[0] + '/' + dateAr[2]
}

function ValidateForm(){
	var dtin=document.forms[1].theDateIn
	var dtout=document.forms[1].DateOut	
	
	var dtinsuccess = isDate(dtin.value, "check in");
	var dtoutsuccess = isDate(dtout.value, "check out");
	var othererror = false;

	if (dtinsuccess == true  && dtoutsuccess == true)
	{
		dtin = reformDate(dtin.value);
		dtout = reformDate(dtout.value);
		
		var dateformatin = new Date(dtin);
		var dateformatout = new Date(dtout);
		
		var daysApart = Math.abs(Math.round(dateformatin-dateformatout)/86400000);	
		if (daysApart < 1)
		{
			//errormessage += " - Your check out date must be after your check in date\n";	
			//othererror = true;
		}
	}

	if (dtinsuccess == false  || dtoutsuccess == false || othererror == true )
	{
		alert(errormessage);
		errormessage = "";
		dtin.focus();
		return false
	}
	document.forms[1].DateIn.value = dtin;
	document.forms[1].Length.value = daysApart;
    return true
 }