var minYear=1900;
var maxYear=2100;
var one_day=1000*60*60*24;
var one_month=1000*60*60*24*30;
var one_year=1000*60*60*24*30*12;


function isInteger(s){
	
    for (var 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 returnString = "";
    // Search through string's characters one by one.
    // If character is not in bag, append to returnString.
    for (var 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(strDay,strMonth,strYear){
	var daysInMonth = DaysArray(12);
	
	var 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);
	getage(strYear, strMonth, strDay);
	if (strMonth.length<1 || month<1 || month>12){
		return false;
	}
	
	if (strDay.length<1 || day<1 || day>31 || (month==2 && day>daysInFebruary(year)) || day > daysInMonth[month]){
		return false;
	}
	if (strYear.length != 4 || year==0 || year<minYear || year>maxYear){
		return false;
	}
	
	return true;
}

function getage(yr, mon, day){
	var today=new Date();
	var pastdate=new Date(yr, mon-1, day);

	var countunit="years";
	var decimals=0;
	var rounding="rounddown";
	var finalunit=(countunit=="days")? one_day : (countunit=="months")? one_month : one_year;
	//alert("finalunit "+finalunit);
	var yearspast=today.getFullYear()-yr-1;
	//alert("yearspast "+yearspast);
	var	tail=(today.getMonth()>mon-1 || today.getMonth()==mon-1 && today.getDate()>=day)? 0 : 1;
	//alert("tail "+tail);
	//pastdate.setFullYear(today.getFullYear());
	//var	pastdate2=new Date(today.getFullYear()-1, mon-1, day);
	
	//tail=(tail==1)? tail+Math.floor((today.getTime()-pastdate.getTime())/(finalunit)*decimals)/decimals : Math.floor((today.getTime()-pastdate2.getTime())/(finalunit)*decimals)/decimals;
	//alert("tail "+tail);
	//alert(yearspast+tail+" "+countunit);
	return yearspast+tail;
}