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 Card", "4", "13,16");
var VisaCard = Cards[1];
Cards[2] = new CardType("American Express Card", "34,37", "15");
var AmExCard = Cards[2];
Cards[3] = new CardType("DinersClub Card", "30,36,38", "14");
var DinersClubCard = Cards[3];
Cards[4] = new CardType("Discover Card", "6011", "16");
var DiscoverCard = Cards[4];
Cards[5] = new CardType("enRoute Card", "2014,2149", "15");
var enRouteCard = Cards[5];
Cards[6] = new CardType("JCB Card", "3088,3096,3112,3158,3337,3528", "16");
var JCBCard = Cards[6];
var LuhnCheckSum = Cards[7] = new CardType();

/*************************************************************************\
CheckCardNumber(form)
function called when users click the "check" button.
\*************************************************************************/
function CheckCardNumber(form) {
var tmpyear;
if (form.CardNumber.value.length == 0) {
alert("Please enter a Card Number.");
form.CardNumber.focus();
return false;
}
if (form.ExpYear.value.length == 0) {
alert("Please enter the Expiration Year.");
form.ExpYear.focus();
return false;
}
if (form.ExpYear.value > 96)
tmpyear = "19" + form.ExpYear.value;
else if (form.ExpYear.value < 21)
tmpyear = "20" + form.ExpYear.value;
else {
alert("The Expiration Year is not valid.");
return false;
}
tmpmonth = form.ExpMon.options[form.ExpMon.selectedIndex].value;
// The following line doesn't work in IE3, you need to change it
// to something like "(new CardType())...".
// if (!CardType().isExpiryDate(tmpyear, tmpmonth)) {
if (!(new CardType()).isExpiryDate(tmpyear, tmpmonth)) {
alert("This card has already expired.");
return false;
}
card = form.CardType.options[form.CardType.selectedIndex].value;
var retval = eval(card + ".checkCardNumber(\"" + form.CardNumber.value +
"\", " + tmpyear + ", " + tmpmonth + ");");
cardname = "";
if (retval)



// comment this out if used on an order form
	return true;
else {
// The cardnumber has the valid luhn checksum, but we want to know which
// cardtype it belongs to.
for (var n = 0; n < Cards.size; n++) {
if (Cards[n].checkCardNumber(form.CardNumber.value, tmpyear, tmpmonth)) {
cardname = Cards[n].getCardType();
break;
   }
}
if (cardname.length > 0) {
alert("This looks like a " + cardname + " number, not a " + card + " number.");
return false;
}
else {
alert("This card number is not valid.");
return false;
      }
   }
}
/*************************************************************************\
Object CardType([String cardtype, String rules, String len, int year, 
                                        int month])
cardtype    : type of card, eg: MasterCard, 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 VisaCard = new CardType("Visa", "4", "16");
var AmExCard = 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())
return false;
if (!this.isExpiryDate())
return false;

return true;
}
/*************************************************************************\
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;
}
 

function isEmail(str) {
  // are regular expressions supported?
  var supported = 0;
  if (window.RegExp) {
    var tempStr = "a";
    var tempReg = new RegExp(tempStr);
    if (tempReg.test(tempStr)) supported = 1;
  }
  if (!supported) 
    return (str.indexOf(".") > 2) && (str.indexOf("@") > 0);
  var r1 = new RegExp("(@.*@)|(\\.\\.)|(@\\.)|(^\\.)");
  var r2 = new RegExp("^.+\\@(\\[?)[a-zA-Z0-9\\-\\.]+\\.([a-zA-Z]{2,3}|[0-9]{1,3})(\\]?)$");
  return (!r1.test(str) && r2.test(str));
}

function verifyForm()
{
  args = verifyForm.arguments;
  if ((args.length < 4) || (((args.length-1) % 3) != 0))
  {
    alert("Not enough arguments! Arguments: " + args.length);
    return false;
  }
  for (i=1; i<args.length; i+=3)
  {
    if (args[i+1] == 0)
    {
      if (eval("document." + args[0] + "." + args[i] + ".value.length") == 0)
      {
        alert("Sorry, we're missing some required information.\nClick OK, and then add information for  " + args[i+2]);
        eval("document." + args[0] + "." + args[i]).focus();
        return false;
      }
    }
    else if (args[i+1] == 1)
    {
      if (eval("document." + args[0] + "." + args[i] + ".options[document." + args[0] + "." + args[i] + ".selectedIndex]" + ".value") == 0)
      {
        alert("Sorry, we're missing some required information.\nClick OK, and then add information for  " + args[i+2]);
        eval("document." + args[0] + "." + args[i]).focus();
        return false;
      }
    }
    else if (args[i+1] == 2)
    {
      if (eval("document." + args[0] + "." + args[i] + ".value") != eval("document." + args[0] + ".confirm" + args[i] + ".value"))
      {
        alert(args[i+2] + " does not match the value of Confirm " + args[i+2]);
        eval("document." + args[0] + "." + args[i]).focus();
        return false;
      }
    }
    else if (args[i+1] == 3)
    {
      if (isEmail(eval("document." + args[0] + "." + args[i] + ".value"))) {
      } else {
        alert(args[i+2] + " does not represent a valid E-Mail address.  Please enter a valid E-Mail address.");
        eval("document." + args[0] + "." + args[i]).focus();
        return false;
      }
    }
    else if (args[i+1] == 4)
    {
      if (eval("document." + args[0] + "." + args[i] + ".value")!="")
        if (isEmail(eval("document." + args[0] + "." + args[i] + ".value"))) {
        } else {
          alert(args[i+2] + " does not represent a valid E-Mail address.  Please enter a valid E-Mail address.");
          eval("document." + args[0] + "." + args[i]).focus();
          return false;
        }
    }
    else if (args[i+1] == 5)
    {
	  if (eval("document." + args[0] + "." + args[i] + ".checked")) {
	  } else {
		  alert(args[i+2]);
    	  return false;
  	  }
    }
    else if (args[i+1] == 6)
    {
      		return CheckCardNumber(eval("document." + args[0]));
    }
    }
  return true;
}