/**
 * DHTML date validation script. Courtesy of SmartWebby.com (http://www.smartwebby.com/dhtml/)
 */
// 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 (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 (strMonth.length < 1 || month < 1 || month > 12){
		//alert("Please enter a valid month")
		return false;
	}
	if (strDay.length < 1 || 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){
		//alert("Please enter a valid 4 digit year between "+minYear+" and "+maxYear)
		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 DateAdd(p_Interval, p_Number, p_Date){
	var dt = new Date(p_Date);
	switch(p_Interval.toLowerCase()){
		case "yyyy": {
			dt.setFullYear(dt.getFullYear() + p_Number);
			break;
		}
		case "q": {
			dt.setMonth(dt.getMonth() + (p_Number*3));
			break;
		}
		case "m": {
			dt.setMonth(dt.getMonth() + p_Number);
			break;
		}
		case "y":			// day of year
		case "d":			// day
		case "w": {		// weekday
			dt.setDate(dt.getDate() + p_Number);
			break;
		}
		case "ww": {	// week of year
			dt.setDate(dt.getDate() + (p_Number*7));
			break;
		}
		case "h": {
			dt.setHours(dt.getHours() + p_Number);
			break;
		}
		case "n": {		// minute
			dt.setMinutes(dt.getMinutes() + p_Number);
			break;
		}
		case "s": {
			dt.setSeconds(dt.getSeconds() + p_Number);
			break;
		}
		case "ms": {	// JS extension
			dt.setMilliseconds(dt.getMilliseconds() + p_Number);
			break;
		}
		default: {
			return "invalid interval: '" + p_Interval + "'";
		}
	}
	return dt;
}