最近做网站用到这个信用卡验证,搜索了些资料,给大家分享.我想大家今后用的着.本来想放到个人博客里的.博客有问题就放在这吧.大家有好的希

信用卡号为16位卡号校验算法：
一、从右边第1位开始往左每隔一位数（右1，3，5...15）相加，和记为sum；二、取右边第2位数，记为R；三、R乘以2，如果乘积小于10，把乘积直接加到sum,如果大于等于10，则把十位数和个位数拆开分别加到sum（如第R为8，乘积是16，则应该把16拆成1和6分别加到sum，结果是1+6+sum）；四、分别取右边第4,6,...16记为R，重复第三步的操作；五、全部加完后，如果sum能被10整除，说明是有效卡，否则无效。
这里有一个简单的例子:假定信用卡号为
4161-1122-1413-12111、1+2+3+4+2+1+1+1（和15）
2、1*2+1*2+1*2+1*2+2*2+1*2+1+2+4*2（和25）
注：粗体部分的1+2是因为(6*2=12=1+2)15+25=40 可以被10整除，说明此卡有效

解决方案 »

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/*****************************/
/*下面是个js验证多种信用卡号的*/
/*****************************/
<HEAD><SCRIPT LANGUAGE="JavaScript">

<!-- Begin
var Cards = new makeArray(8);
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("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(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;
}
if (form.ExpYear.value.length == 0) {
alert("Please enter the Expiration Year.");
form.ExpYear.focus();
return;
}
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;
}
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;
}
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
alert("This card number appears to be valid.");
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.");
}
else {
alert("This card number is not valid.");
      }
   }
}
/*************************************************************************\
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;
}
//  End -->
</script>
</HEAD>
<BODY><center>
<form name="ThisForm">
Card Number: <input name="CardNumber" size="16" maxlength="19"><br>
Card Type:
<select name="CardType">
<option value="MasterCard">MasterCard
<option value="VisaCard">Visa
<option value="AmExCard">American Express
<option value="DinersClubCard">Diners Club
<option value="DiscoverCard">Discover
<option value="enRouteCard">enRoute
<option value="JCBCard">JCB
</select>
<br>
Expiration Date: Month
<select name="ExpMon">
<option value="1" selected>1
<option value="2">2
<option value="3">3
<option value="4">4
<option value="5">5
<option value="6">6
<option value="7">7
<option value="8">8
<option value="9">9
<option value="10">10
<option value="11">11
<option value="12">12
</select>
Year <input name="ExpYear" size="2" maxlength="2">(Range: 1997~2020)<br>
<input type="button" value="Check" OnClick="CheckCardNumber(this.form)"><br>
</form>
</center><p><center>
<font face="arial, helvetica" size="-2">Free JavaScripts provided<br>
by <a href="http://javascriptsource.com">The JavaScript Source</a></font>
</center><p>
帮忙http://community.csdn.net/Expert/topic/4999/4999993.xml?temp=.1140558