var Cards = new makeArray(5);
Cards[0] = new CardType("MasterCard", "51,52,53,54,55", "16");
var MasterCard = Cards[0];
Cards[1] = new CardType("VisaCard", "4", "13,16");
var VisaCard = Cards[1];
Cards[2] = new CardType("AmExCard", "34,37", "15");
var AmExCard = Cards[2];
Cards[3] = new CardType("DinersClubCard", "30,36,38", "14");
var DinersClubCard = Cards[3];
Cards[4] = new CardType("JCBCard", "3088,3096,3112,3158,3337,3528,3529,353,354,355,356,357,3580,3581,3582,3583,3584,3585,3586,3587,3588,3589,3566,3540,3541", "16");
var JCBCard = Cards[4];
//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", "3088,3096,3112,3158,3337,3528,3529,353,354,355,356,357,3580,3581,3582,3583,3584,3585,3586,3587,3588,3589,3566,3540,3541", "16");
//var JCBCard = Cards[6];
var LuhnCheckSum = Cards[5] = new CardType();

/*************************************************************************\
  CheckCardNumber(form)
  function called when users click the "check" button.
\*************************************************************************/
function CheckCardNumber(form) {
  var tmpyear;
  if (form.cc_number.value.length == 0) {
    alert("Please key in Card Number.");
    form.cc_number.focus();
    return false;
  }
  if (form.cc_name.value.length == 0) {
    alert("Please key in Name on Card.");
    form.cc_name.focus();
    return false;
  }
  if (form.cc_year.value.length == 0) {
    alert("Please key in Expiry Year.");
    form.cc_year.focus();
    return false;
  }
  if (form.cc_year.value > 96)
    tmpyear = "19" + form.cc_year.value;
  else if (form.cc_year.value < 21)
    tmpyear = "20" + form.cc_year.value;
  else {
    alert("bad year");
    return false;
  }
  tmpmonth = form.cc_month.options[form.cc_month.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("expiry date passed already.");
    return false;
  }
  //card = form.cc_type.options[form.cc_type.selectedIndex].value;
  //card="MasterCard";
  card=form.cc_type.value;
  //alert(card);
  var retval = eval(card + ".checkCardNumber(\"" + form.cc_number.value +
        "\", " + tmpyear + ", " + tmpmonth + ");");
		
  cardname = "";
  if (retval)
    // The cardnumber has the valid luhn checksum and matches the
    // cardtype's rule.
    //alert("correct");
    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.cc_number.value, tmpyear, tmpmonth)) {
        cardname = Cards[n].getCardType();
        break;
      }
	  
    }
   if (cardname.length > 0) {
      alert("This's " + cardname + " number, not " + card + " number.");
	   return false;
    }
    else {
      alert("This's not a card number.");
	   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";

  // set CardNumber method.
  this.setCardNumber = setCardNumber;

  // setCardType method.
  this.setCardType = setCardType;

  // setLen method.
  this.setLen = setLen;

  // setRules method.
  this.setRules = setRules;

  // setExpiryDate method.
  this.setExpiryDate = setExpiryDate;

  this.setCardType(tmpcardtype);
  this.setLen(tmplen);
  this.setRules(tmprules);
  if (argc > 4)
    this.setExpiryDate(argv[3], argv[4]);

  // checkCardNumber method.
  this.checkCardNumber = checkCardNumber;

  // getExpiryDate method.
  this.getExpiryDate = getExpiryDate;

  // getCardType method.
  this.getCardType = getCardType;

  // isCardNumber method.
  this.isCardNumber = isCardNumber;

  // isExpiryDate method.
  this.isExpiryDate = isExpiryDate;

  // luhnCheck method.
  this.luhnCheck = luhnCheck;

  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);
  //alert(today.getTime());
  //alert(expiry.getTime());
  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;
}