<!-- Original:  Simon Tneoh (tneohcb@pc.jaring.my) -->

<!-- This script and many more are available free online at -->
<!-- The JavaScript Source!! http://javascript.internet.com -->

<!-- Begin
var Cards = new makeArray(8);
Cards[0] = new b_cardtype("MasterCard", "51,52,53,54,55", "16");
var MasterCard = Cards[0];
Cards[1] = new b_cardtype("VisaCard", "4", "13,16");
var VisaCard = Cards[1];
Cards[2] = new b_cardtype("AmExCard", "34,37", "15");
var AmExCard = Cards[2];
Cards[3] = new b_cardtype("DinersClubCard", "30,36,38", "14");
var DinersClubCard = Cards[3];
Cards[4] = new b_cardtype("DiscoverCard", "6011", "16");
var DiscoverCard = Cards[4];
Cards[5] = new b_cardtype("enRouteCard", "2014,2149", "15");
var enRouteCard = Cards[5];
Cards[6] = new b_cardtype("JCBCard", "3088,3096,3112,3158,3337,3528", "16");
var JCBCard = Cards[6];
var LuhnCheckSum = Cards[7] = new b_cardtype();

/****** Check for Non-Integer Characters ***********/
function checkString(myString) {
    var isInteger = new Boolean()
    isInteger=true
    var myChar=""
    var myInt=0

    if (myString!="" && typeof(myString)=="string") {
        for (i=0;i<myString.length;i++) {
            myChar=myString.charAt(i)
            myInt=parseInt(myChar)

            if (isNaN(myInt)) {
                isInteger=false
            }
        }

    } else {
        isInteger=false
    }

    return isInteger
}

/****** End Check for Non-Integer Characters ***********/

/*************************************************************************\
Checkb_cardnumber(form)
function called when users click the "check" button.
\*************************************************************************/
function Checkb_cardnumber(form) {
var tmpyear;
if (form.b_cardnumber.value.length == 0) {
alert("Please enter a Card Number.");
form.b_cardnumber.focus();
return false;
}
if (form.b_month.value.length == 0) {
alert("Please enter the Expiration Month.");
form.b_month.focus();
return false;
}
if (form.b_year.value.length == 0) {
alert("Please enter the Expiration Year.");
form.b_year.focus();
return false;
}
if (form.b_cid.value.length == 0) {
alert("Please enter CID number.");
form.b_cid.focus();
return false;
}

if (form.b_cardtype.value == "AmExCard") {
   if (form.b_cid.value.length < 4) {
      alert("CID must be 4 Digits American Express");
      form.b_cid.focus();
      return false;
   }
}
else {
   if (form.b_cid.value.length != 3) {
      alert("CID must be 3 Digits for MasterCard or Visa");
      form.b_cid.focus();
      return false;
      }
}


if (!checkString(form.b_cid.value)) {
   alert("CID Must be Number Only.");
   form.b_cid.focus();
   return false;
}


tmpyear = form.b_year.value;
tmpmonth = form.b_month.options[form.b_month.selectedIndex].value;
// The following line doesn't work in IE3, you need to change it
// to something like "(new b_cardtype())...".
// if (!b_cardtype().isExpiryDate(tmpyear, tmpmonth)) {
if (!(new b_cardtype()).isExpiryDate(tmpyear, tmpmonth)) {
alert("This card has already expired.");
return false;
}
card = form.b_cardtype.options[form.b_cardtype.selectedIndex].value;
var retval = eval(card + ".checkb_cardnumber(\"" + form.b_cardnumber.value +
"\", " + tmpyear + ", " + tmpmonth + ");");
cardname = "";

if (retval) {
   // comment this out if used on an order form
  //alert("This card number appears to be valid.");
  return true;
}
else {
// The b_cardnumber has the valid luhn checksum, but we want to know which
// b_cardtype it belongs to.
for (var n = 0; n < Cards.size; n++) {
if (Cards[n].checkb_cardnumber(form.b_cardnumber.value, tmpyear, tmpmonth)) {
cardname = Cards[n].getb_cardtype();
break;
   }
}

if (cardname.length > 0) {
alert("This looks like a " + cardname + " number, not a " + card + " number.");
}
else {
alert("Please enter a valid credit card number.");
     return false;
      }
   }
}
/*************************************************************************\
Object b_cardtype([String b_cardtype, String rules, String len, int year,
                                        int month])
b_cardtype    : type of card, eg: MasterCard, Visa, etc.
rules       : rules of the b_cardnumber, eg: "4", "6011", "34,37".
len         : valid length of b_cardnumber, eg: "16,19", "13,16".
year        : year of expiry date.
month       : month of expiry date.
eg:
var VisaCard = new b_cardtype("Visa", "4", "16");
var AmExCard = new b_cardtype("AmEx", "34,37", "15");
\*************************************************************************/
function b_cardtype() {
var n;
var argv = b_cardtype.arguments;
var argc = b_cardtype.arguments.length;

this.objname = "object b_cardtype";

var tmpb_cardtype = (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.setb_cardnumber = setb_cardnumber;  // set b_cardnumber method.
this.setb_cardtype = setb_cardtype;  // setb_cardtype method.
this.setLen = setLen;  // setLen method.
this.setRules = setRules;  // setRules method.
this.setExpiryDate = setExpiryDate;  // setExpiryDate method.

this.setb_cardtype(tmpb_cardtype);
this.setLen(tmplen);
this.setRules(tmprules);
if (argc > 4)
this.setExpiryDate(argv[3], argv[4]);

this.checkb_cardnumber = checkb_cardnumber;  // checkb_cardnumber method.
this.getExpiryDate = getExpiryDate;  // getExpiryDate method.
this.getb_cardtype = getb_cardtype;  // getb_cardtype method.
this.isb_cardnumber = isb_cardnumber;  // isb_cardnumber method.
this.isExpiryDate = isExpiryDate;  // isExpiryDate method.
this.luhnCheck = luhnCheck;// luhnCheck method.
return this;
}

/*************************************************************************\
boolean checkb_cardnumber([String b_cardnumber, int year, int month])
return true if b_cardnumber pass the luhncheck and the expiry date is
valid, else return false.
\*************************************************************************/
function checkb_cardnumber() {
var argv = checkb_cardnumber.arguments;
var argc = checkb_cardnumber.arguments.length;
var b_cardnumber = (argc > 0) ? argv[0] : this.b_cardnumber;
var year = (argc > 1) ? argv[1] : this.year;
var month = (argc > 2) ? argv[2] : this.month;

this.setb_cardnumber(b_cardnumber);
this.setExpiryDate(year, month);

if (!this.isb_cardnumber())
return false;
if (!this.isExpiryDate())
return false;

return true;
}
/*************************************************************************\
String getb_cardtype()
return the b_cardtype.
\*************************************************************************/
function getb_cardtype() {
return this.b_cardtype;
}
/*************************************************************************\
String getExpiryDate()
return the expiry date.
\*************************************************************************/
function getExpiryDate() {
return this.month + "/" + this.year;
}
/*************************************************************************\
boolean isb_cardnumber([String b_cardnumber])
return true if b_cardnumber pass the luhncheck and the rules, else return
false.
\*************************************************************************/
function isb_cardnumber() {
var argv = isb_cardnumber.arguments;
var argc = isb_cardnumber.arguments.length;
var b_cardnumber = (argc > 0) ? argv[0] : this.b_cardnumber;
if (!this.luhnCheck())
return false;

for (var n = 0; n < this.len.size; n++)
if (b_cardnumber.toString().length == this.len[n]) {
for (var m = 0; m < this.rules.size; m++) {
var headdigit = b_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 b_cardnumber])
return true if b_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 b_cardnumber = argc > 0 ? argv[0] : this.b_cardnumber;

if (! isNum(b_cardnumber)) {
return false;
  }

var no_digit = b_cardnumber.length;
var oddoeven = no_digit & 1;
var sum = 0;

for (var count = 0; count < no_digit; count++) {
var digit = parseInt(b_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;
}

/*************************************************************************\
b_cardtype setb_cardnumber(b_cardnumber)
return the b_cardtype object.
\*************************************************************************/
function setb_cardnumber(b_cardnumber) {
this.b_cardnumber = b_cardnumber;
return this;
}

/*************************************************************************\
b_cardtype setb_cardtype(b_cardtype)
return the b_cardtype object.
\*************************************************************************/
function setb_cardtype(b_cardtype) {
this.b_cardtype = b_cardtype;
return this;
}

/*************************************************************************\
b_cardtype setExpiryDate(year, month)
return the b_cardtype object.
\*************************************************************************/
function setExpiryDate(year, month) {
this.year = year;
this.month = month;
return this;
}

/*************************************************************************\
b_cardtype setLen(len)
return the b_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;
}

/*************************************************************************\
b_cardtype setRules()
return the b_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;
}
//  End -->