cardError = false;
var errs = "";
var msg  = "______________________________________________________\n\n"
msg += "The form was not submitted because of the following error(s).\n";
msg += "Please correct these error(s) and re-submit.\n";
msg += "______________________________________________________\n\n"


var Cards = new makeArray(8);
    Cards[0] = new CardType("MASTERCARD", "51,52,53,54,55", "16");

var MASTERCARD = Cards[0];
    Cards[1] = new CardType("VISA", "4", "13,16");

var VISA = Cards[1];
    Cards[2] = new CardType("AMEX", "34,37", "15");

var AMEX = Cards[2];
    Cards[3] = new CardType("DinersClubCard", "30,36,38", "14");

var DinersClubCard = Cards[3];
    Cards[4] = new CardType("DiscoverCard", "6011", "16");

var DiscoverCard = Cards[4];
    Cards[5] = new CardType("enRouteCard", "2014,2149", "15");

var enRouteCard = Cards[5];
    Cards[6] = new CardType("JCBCard", "3088,3096,3112,3158,3337,3528", "16");

var JCBCard = Cards[6];

var LuhnCheckSum = Cards[7] = new CardType();

/*************************************************************************\
CheckCardNumber()
function called when users click the "check" button.
\*************************************************************************/
function CheckCardNumber() 
{
	var tmpyear;
	var tmpmonth;

	ccNumber   = document.newCustomer.ccno.value;


	ccHolder   = document.newCustomer.ccholder.value;
	ccType     = document.newCustomer.typeOf.options[document.newCustomer.typeOf.selectedIndex].value;
	tmpMonth   = document.newCustomer.month.options[document.newCustomer.month.selectedIndex].value;
	tmpYear    = document.newCustomer.year.options[document.newCustomer.year.selectedIndex].value;

	fErr = false;	
	if(ccNumber.length <= 0)
	{
		errs += "\tYou Must Enter A Credit Card Number\n\n";
	 	fErr = true;	
		alert(msg + errs);
		errs = "";
		return false;
	}

	if(ccType.length == 0 )
	{
		errs  += "\tYou Must Enter A Credit Card Type\n\n";
	 	fErr = true;	
		alert(msg + errs);
		errs = "";
		return false;
	}	

 	if(ccHolder.length == 0)
	{
		errs += "\tYou Must Enter The Name Of The Card Holder\n\n";
	 	fErr = true;	
		alert(msg + errs);
		errs = "";
		return false;
	}

	card = ccType;
	retval = eval(card + ".checkCardNumber(\"" + ccNumber + "\", " + tmpYear + ", " + tmpMonth + ");");
	// alert(card + ".checkCardNumber(\"" + ccNumber + "\", " + tmpYear + ", " + tmpMonth + ");");

	if (  errs.length > 0 )
	{
		alert(msg + errs);
		errs = "";
		return false;
	}
	else
		return true;

}

/*************************************************************************\
Object CardType([String cardtype, String rules, String len, int year,
                                        int month])
cardtype    : type of card, eg: MC, Visa, etc.
rules       : rules of the cardnumber, eg: "4", "6011", "34,37".
len         : valid length of cardnumber, eg: "16,19", "13,16".
year        : year of expiry date.
month       : month of expiry date.
eg:
var V = new CardType("Visa", "4", "16");
var AMEX = new CardType("AmEx", "34,37", "15");
\*************************************************************************/
function CardType() 
{
	var n;
	var argv = CardType.arguments;
	var argc = CardType.arguments.length;

	this.objname = "object CardType";

	var tmpcardtype = (argc > 0) ? argv[0] : "CardObject";
	var tmprules = (argc > 1) ? argv[1] : "0,1,2,3,4,5,6,7,8,9";
	var tmplen = (argc > 2) ? argv[2] : "13,14,15,16,19";

	this.setCardNumber = setCardNumber;  // set CardNumber method.
	this.setCardType = setCardType;  // setCardType method.
	this.setLen = setLen;  // setLen method.
	this.setRules = setRules;  // setRules method.
	this.setExpiryDate = setExpiryDate;  // setExpiryDate method.

	this.setCardType(tmpcardtype);
	this.setLen(tmplen);
	this.setRules(tmprules);

	if (argc > 4)
		this.setExpiryDate(argv[3], argv[4]);

	this.checkCardNumber = checkCardNumber; // checkCardNumber method.
	this.getExpiryDate = getExpiryDate;  	// getExpiryDate method.
	this.getCardType = getCardType;  	// getCardType method.
	this.isCardNumber = isCardNumber;  	// isCardNumber method.
	this.isExpiryDate = isExpiryDate;  	// isExpiryDate method.
	this.luhnCheck = luhnCheck;		// luhnCheck method.

	
	return this;

}

/*************************************************************************\
boolean checkCardNumber([String cardnumber, int year, int month])
return true if cardnumber pass the luhncheck and the expiry date is
valid, else return false.
\*************************************************************************/
function checkCardNumber() 
{
	var argv = checkCardNumber.arguments;
	var argc = checkCardNumber.arguments.length;
	var cardnumber = (argc > 0) ? argv[0] : this.cardnumber;
	var year = (argc > 1) ? argv[1] : this.year;
	var month = (argc > 2) ? argv[2] : this.month;

	this.setCardNumber(cardnumber);
	this.setExpiryDate(year, month);

	if (!this.isCardNumber())
	{
		errs += "\tBad Card Number\n\n";
	}
	if (!this.isExpiryDate())
	{
		errs += "\tExpiration Date Is Not Valid\n\n";
	}
	return 0;
}

/*************************************************************************\
String getCardType()
return the cardtype.
\*************************************************************************/
function getCardType() 
{
	return this.cardtype;
}

/*************************************************************************\
String getExpiryDate()
return the expiry date.
\*************************************************************************/
function getExpiryDate() 
{
	return this.month + "/" + this.year;
}

/*************************************************************************\
boolean isCardNumber([String cardnumber])
return true if cardnumber pass the luhncheck and the rules, else return
false.
\*************************************************************************/
function isCardNumber() 
{
	var argv = isCardNumber.arguments;
	var argc = isCardNumber.arguments.length;
	var cardnumber = (argc > 0) ? argv[0] : this.cardnumber;

	if (!this.luhnCheck())
		return false;

	for (var n = 0; n < this.len.size; n++)
	if (cardnumber.toString().length == this.len[n]) 
	{
		for (var m = 0; m < this.rules.size; m++) 
		{
			var headdigit = cardnumber.substring(0, this.rules[m].toString().length);
			if (headdigit == this.rules[m])
			return true;
		}

	return false;

	}

	return false;
}

/*************************************************************************\
boolean isExpiryDate([int year, int month])
return true if the date is a valid expiry date,
else return false.
\*************************************************************************/
function isExpiryDate() 
{
	var argv = isExpiryDate.arguments;
	var argc = isExpiryDate.arguments.length;

	year = argc > 0 ? argv[0] : this.year;
	month = argc > 1 ? argv[1] : this.month;

	if (!isNum(year+""))
		return false;

	if (!isNum(month+""))
		return false;

	today = new Date();
	expiry = new Date(year, month);

	if (today.getTime() > expiry.getTime())
		return false;
	else
		return true;
}

/*************************************************************************\
boolean isNum(String argvalue)
return true if argvalue contains only numeric characters,
else return false.
\*************************************************************************/
function isNum(argvalue) 
{
	argvalue = argvalue.toString();

	if (argvalue.length == 0)
		return false;

	for (var n = 0; n < argvalue.length; n++)
		if (argvalue.substring(n, n+1) < "0" || argvalue.substring(n, n+1) > "9")
			return false;

	return true;
}

/*************************************************************************\
boolean luhnCheck([String CardNumber])
return true if CardNumber pass the luhn check else return false.
Reference: http://www.ling.nwu.edu/~sburke/pub/luhn_lib.pl
\*************************************************************************/
function luhnCheck() 
{
	var argv = luhnCheck.arguments;
	var argc = luhnCheck.arguments.length;

	var CardNumber = argc > 0 ? argv[0] : this.cardnumber;

	if (! isNum(CardNumber)) 
	{
		return false;
  	}

	var no_digit = CardNumber.length;
	var oddoeven = no_digit & 1;
	var sum = 0;

	for (var count = 0; count < no_digit; count++) 
	{
		var digit = parseInt(CardNumber.charAt(count));
		if (!((count & 1) ^ oddoeven)) 
		{
			digit *= 2;
			if (digit > 9)
				digit -= 9;
		}

		sum += digit;
	}

	if (sum % 10 == 0)
		return true;
	else
		return false;
}

/*************************************************************************\
ArrayObject makeArray(int size)
return the array object in the size specified.
\*************************************************************************/
function makeArray(size) 
{
	this.size = size;
	return this;
}

/*************************************************************************\
CardType setCardNumber(cardnumber)
return the CardType object.
\*************************************************************************/
function setCardNumber(cardnumber) 
{
	this.cardnumber = cardnumber;
	return this;
}

/*************************************************************************\
CardType setCardType(cardtype)
return the CardType object.
\*************************************************************************/
function setCardType(cardtype) 
{
	this.cardtype = cardtype;
	return this;
}

/*************************************************************************\
CardType setExpiryDate(year, month)
return the CardType object.
\*************************************************************************/
function setExpiryDate(year, month) 
{
	this.year = year;
	this.month = month;
	return this;
}

/*************************************************************************\
CardType setLen(len)
return the CardType object.
\*************************************************************************/
function setLen(len) 
{
	// Create the len array.
	if (len.length == 0 || len == null)
		len = "13,14,15,16,19";

	var tmplen = len;
	n = 1;

	while (tmplen.indexOf(",") != -1) 
	{
		tmplen = tmplen.substring(tmplen.indexOf(",") + 1, tmplen.length);
		n++;
	}

	this.len = new makeArray(n);
	n = 0;

	while (len.indexOf(",") != -1) 
	{
		var tmpstr = len.substring(0, len.indexOf(","));
		this.len[n] = tmpstr;
		len = len.substring(len.indexOf(",") + 1, len.length);
		n++;
	}

	this.len[n] = len;
	return this;

}

/*************************************************************************\
CardType setRules()
return the CardType object.
\*************************************************************************/
function setRules(rules) 
{
	// Create the rules array.
	if (rules.length == 0 || rules == null)
		rules = "0,1,2,3,4,5,6,7,8,9";

	var tmprules = rules;
	n = 1;
	while (tmprules.indexOf(",") != -1) 
	{
		tmprules = tmprules.substring(tmprules.indexOf(",") + 1, tmprules.length);
		n++;
	}

	this.rules = new makeArray(n);
	n = 0;

	while (rules.indexOf(",") != -1) 
	{
		var tmpstr = rules.substring(0, rules.indexOf(","));
		this.rules[n] = tmpstr;
		rules = rules.substring(rules.indexOf(",") + 1, rules.length);
		n++;
	}

	this.rules[n] = rules;

	return this;
}