How to validate a credit card number

Question

I just want to validate a credit card number in the JavaScript code  I have used a regular expression for digit numbers  but I don t know why it is not working   Here is my function as per below   function validate creditcardnumber         var re16digit      d 16        if  document myform CreditCardNumber value search re16digit     -1          alert  Please enter your 16 digit credit card numbers        return false

User · Answer

I hope the following two links help to solve your problem.

FYI, various credit cards are available in the world. So, your thought is wrong. Credit cards have some format. See the following links. The first one is pure JavaScript and the second one is using jQuery.

Demo:

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function testCreditCard() {_x000D_
  myCardNo = document.getElementById('CardNumber').value;_x000D_
  myCardType = document.getElementById('CardType').value;_x000D_
  if (checkCreditCard(myCardNo, myCardType)) {_x000D_
    alert("Credit card has a valid format")_x000D_
  } else {_x000D_
    alert(ccErrors[ccErrorNo])_x000D_
  };_x000D_
}

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<script src="https://www.braemoor.co.uk/software/_private/creditcard.js"></script>_x000D_
_x000D_
<!-- COPIED THE DEMO CODE FROM THE SOURCE WEBSITE (https://www.braemoor.co.uk/software/creditcard.shtml) -->_x000D_
_x000D_
<table>_x000D_
  <tbody>_x000D_
    <tr>_x000D_
      <td style="padding-right: 30px;">American Express</td>_x000D_
      <td>3400 0000 0000 009</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>Carte Blanche</td>_x000D_
      <td>3000 0000 0000 04</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>Discover</td>_x000D_
      <td>6011 0000 0000 0004</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>Diners Club</td>_x000D_
      <td>3852 0000 0232 37</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>enRoute</td>_x000D_
      <td>2014 0000 0000 009</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>JCB</td>_x000D_
      <td>3530 111333300000</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>MasterCard</td>_x000D_
      <td>5500 0000 0000 0004</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>Solo</td>_x000D_
      <td>6334 0000 0000 0004</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>Switch</td>_x000D_
      <td>4903 0100 0000 0009</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>Visa</td>_x000D_
      <td>4111 1111 1111 1111</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>Laser</td>_x000D_
      <td>6304 1000 0000 0008</td>_x000D_
    </tr>_x000D_
  </tbody>_x000D_
</table>_x000D_
<hr /> Card Number:_x000D_
<select tabindex="11" id="CardType" style="margin-left: 10px;">_x000D_
  <option value="AmEx">American Express</option>_x000D_
  <option value="CarteBlanche">Carte Blanche</option>_x000D_
  <option value="DinersClub">Diners Club</option>_x000D_
  <option value="Discover">Discover</option>_x000D_
  <option value="EnRoute">enRoute</option>_x000D_
  <option value="JCB">JCB</option>_x000D_
  <option value="Maestro">Maestro</option>_x000D_
  <option value="MasterCard">MasterCard</option>_x000D_
  <option value="Solo">Solo</option>_x000D_
  <option value="Switch">Switch</option>_x000D_
  <option value="Visa">Visa</option>_x000D_
  <option value="VisaElectron">Visa Electron</option>_x000D_
  <option value="LaserCard">Laser</option>_x000D_
</select> <input type="text" id="CardNumber" maxlength="24" size="24" style="margin-left: 10px;"> <button id="mybutton" type="button" onclick="testCreditCard();" style="margin-left: 10px; color: #f00;">Check</button>_x000D_
_x000D_
<p style="color: red; font-size: 10px;"> COPIED THE DEMO CODE FROM TEH SOURCE WEBSITE (https://www.braemoor.co.uk/software/creditcard.shtml) </p>

_x000D_

User · Answer

Luhn s algorithm is used for adding validation of credit and debit card numbers  This JavaScript function should work out   function validate creditcardnumber inputNum        var digit  digits  flag  sum   i   len      flag   true      sum   0      digits    inputNum       split     reverse        for   i   0   len   digits length   i  lt   len   i            digit   digits  i         digit   parseInt digit  10         if   flag    flag             digit    2                if  digit  gt  9            digit -  9                sum    digit            return sum   10     0

User · Answer

Use this   function AmexCardnumber inputtxt      var cardno        3 47  0-9  13        return cardno test inputtxt      function VisaCardnumber inputtxt      var cardno        4 0-9  12     0-9  3          return cardno test inputtxt      function MasterCardnumber inputtxt      var cardno        5 1-5  0-9  14        return cardno test inputtxt      function DiscoverCardnumber inputtxt      var cardno        6   011 5 0-9  0-9   0-9  12        return cardno test inputtxt      function DinerClubCardnumber inputtxt      var cardno        3   0 0-5   68  0-9   0-9  11        return cardno test inputtxt      function JCBCardnumber inputtxt      var cardno           2131 1800 35 d 3   d 11        return cardno test inputtxt      function IsValidCreditCardNumber cardNumber       var cardType   null    if  VisaCardnumber cardNumber         cardType    visa       else if  MasterCardnumber cardNumber         cardType    mastercard       else if  AmexCardnumber cardNumber         cardType    americanexpress       else if  DiscoverCardnumber cardNumber         cardType    discover       else if  DinerClubCardnumber cardNumber         cardType    dinerclub       else if  JCBCardnumber cardNumber         cardType    jcb          return cardType

User · Answer

You can use this snippet to validate 16 digits card numbers with the Luhn algorithm   function validateCardNumber number        var regex   new RegExp    0-9  16          if   regex test number           return false       return luhnCheck number      function luhnCheck val        var sum   0      for  var i   0  i  lt  val length  i              var intVal   parseInt val substr i  1            if  i   2    0                intVal    2              if  intVal  gt  9                    intVal   1    intVal   10                                   sum    intVal            return  sum   10     0

User · Answer

http   www w3resource com javascript form credit-card-validation php   the Luhn algorithm  var checkLuhn   function  cardNo        var s   0      var doubleDigit   false      for  var i   cardNo length - 1  i  gt   0  i--            var digit    cardNo i           if  doubleDigit                digit    2              if  digit  gt  9                  digit -  9                    s    digit          doubleDigit    doubleDigit            return s   10    0     P S   Do not use regex for this  as it is done by the link  But it is useful to use text definitions of each card  Here it is   American Express  Starting with 34 or 37  length 15 digits  Visa  Starting with 4  length 13 or 16 digits  MasterCard  Starting with 51 through 55  length 16 digits  Discover  Starting with 6011  length 16 digits or starting with 5  length 15 digits  Diners Club  Starting with 300 through 305  36  or 38  length 14 digits  JCB  Starting with 2131 or 1800  length 15 digits or starting with 35  length 16 digits   I have it done like this  var validateCardNo   function  no        return  no  amp  amp  checkLuhn no   amp  amp          no length    16  amp  amp   no 0     4    no 0     5  amp  amp  no 1   gt   1  amp  amp  no 1   lt   5             no indexOf  quot 6011 quot      0    no indexOf  quot 65 quot      0              no length    15  amp  amp   no indexOf  quot 34 quot      0    no indexOf  quot 37 quot      0             no length    13  amp  amp  no 0     4

User · Answer

A credit card number is not a bunch of random numbers  There is a formula for checking if it is correct   After a quick Google search I found this JavaScript which will check a credit card number to be valid   http   javascript internet com forms credit-card-number-validation html  URL Broken  Internet archive  http   web archive org web 20100129174150 http   javascript internet com forms credit-card-number-validation html    lt  -- TWO STEPS TO INSTALL CREDIT CARD NUMBER VALIDATION     1   Copy the code into the HEAD of your HTML document   2   Add the last code into the BODY of your HTML document  -- gt    lt  -- STEP ONE  Paste this code into the HEAD of your HTML document  -- gt    lt HEAD gt      lt script type  text javascript  gt       lt  --        This script and many more are available free online at     The JavaScript Source   http   javascript internet com     Created by  David Leppek    https   www azcode com Mod10      Basically  the algorithm takes each digit  from right to left and muliplies each second     digit by two  If the multiple is two-digits long  i e   6   2   12  the two digits of     the multiple are then added together for a new number  1   2   3   You then add up the     string of numbers  both unaltered and new values and get a total sum  This sum is then     divided by 10 and the remainder should be zero if it is a valid credit card  Hense the     name Mod 10 or Modulus 10             function Mod10 ccNumb        v2 0       var valid    0123456789      Valid digits in a credit card number       var len   ccNumb length      The length of the submitted cc number       var iCCN   parseInt ccNumb       Integer of ccNumb       var sCCN   ccNumb toString        String of ccNumb       sCCN   sCCN replace     s   s   g          Strip spaces       var iTotal   0      Integer total set at zero       var bNum   true      By default assume it is a number       var bResult   false      By default assume it is NOT a valid cc       var temp      Temporary variable for parsing string       var calc      Used for calculation of each digit           Determine if the ccNumb is in fact all numbers       for  var j 0  j lt len  j              temp        sCCN substring j  j 1           if  valid indexOf temp      -1              bNum   false                              If it is NOT a number  you can either alert to the fact  or just pass a failure       if   bNum               alert  Not a Number               bResult   false                    Determine if it is the proper length       if   len    0   amp  amp   bResult         Nothing  the field is blank AND passed above   check         bResult   false                else      ccNumb is a number and the proper length - let s                  see if it is a valid card number          if  len  gt   15        15 or 16 for Amex or V MC           for  var i len i gt 0 i--        LOOP through the digits of the card             calc   parseInt iCCN    10      Right most digit             calc   parseInt calc       Assure it is an integer             iTotal    calc      Running total of the card number as we loop - Do Nothing to first digit             i--      Decrement the count - move to the next digit in the card             iCCN   iCCN   10                                   Subtracts right most digit from ccNumb             calc   parseInt iCCN    10         NEXT right most digit             calc   calc  2                                     multiply the digit by two                 Instead of some screwy method of converting 16 to a string                and then parsing 1 and 6 and then adding them to make 7                 I use a simple switch statement to change the value                of calc2 to 7 if 16 is the multiple              switch calc                  case 10  calc   1  break      5 2 10  amp  1 0   1               case 12  calc   3  break      6 2 12  amp  1 2   3               case 14  calc   5  break      7 2 14  amp  1 4   5               case 16  calc   7  break      8 2 16  amp  1 6   7               case 18  calc   9  break      9 2 18  amp  1 8   9               default  calc   calc          4 2  8  amp    8   8  - the same for all lower numbers                           iCCN   iCCN   10      Subtracts right most digit from ccNum             iTotal    calc      Running total of the card number as we loop                END OF LOOP            if   iTotal 10   0       Check to see if the sum Mod 10 is zero             bResult   true      This IS  or could be  a valid credit card number                        else               bResult   false      This could NOT be a valid credit card number                                         Change alert to on-page display or other indication as needed        if  bResult            alert  This IS a valid Credit Card Number                   if   bResult            alert  This is NOT a valid Credit Card Number                   return bResult     Return the results              -- gt     lt  script gt    lt  HEAD gt     lt  -- STEP TWO  Copy this code into the BODY of your HTML document  -- gt    lt BODY gt    lt div align  center  gt     lt form name  Form1  gt       lt table width  50   border  0  cellspacing  0  cellpadding  5  gt         lt tr gt           lt td width  50   align  right  gt Credit Card Number     lt  td gt           lt td width  50   gt             lt input name  CreditCard  type  text  value  4012888888881881  size  18  maxlength  16  style  border  1px solid  000098  padding  3px   gt           lt  td gt         lt  tr gt         lt tr gt           lt td colspan  2  align  center  gt             lt input type  button  name  Button  style  color   fff  background   000098  font-weight bold  border  solid 1px  000   value  TEST CARD NUMBER  onClick  return Mod10 document Form1 CreditCard value    gt           lt  td gt         lt  tr gt       lt  table gt     lt  form gt   lt  div gt    lt p gt  lt center gt     lt font face  arial  helvetica  size -2  gt Free JavaScripts provided lt br gt    by  lt a href  http   javascriptsource com  gt The JavaScript Source lt  a gt  lt  font gt   lt  center gt  lt p gt    lt  -- Script Size   4 97 KB -- gt

User · Answer

You define the variable name re16digit but later refer to it as re10digit  which will throw an error   To simplify your code  you should use RegExp prototype test   rather than String prototype search     function validate creditcardnumber         var re16digit      d 16         if   re16digit test document myform CreditCardNumber value             alert  Please enter your 16 digit credit card numbers            return false               Working demo  http   jsfiddle net Dxjkh    As others have mentioned  you may be better off using a JavaScript implementation of the Luhn Algorithm   It s also worth mentioning that a check for 16 digits will fail for American Express  15 digits  and Diners  14 digits  cards

User · Answer

This works  http   jsfiddle net WHKeK   function validate creditcardnumber         var re16digit    d 16        if  document myform CreditCardNumber value search re16digit     -1          alert  Please enter your 16 digit credit card numbers        return false          You have a typo  You call the variable re16digit  but in your search you have re10digit

User · Answer

This code works   function check credit card validity contact bank random id        var cb visa pattern     4       var cb mast pattern     5 1-5        var cb amex pattern     3 47        var cb disc pattern     6 011 5 4 4-9  22 12 6-9  1 3-9  0-9   2-8  0-9  2  9 0-1  0-9  92 0-5          var credit card number   jQuery   credit card number text field   random id  val        var cb is visa   cb visa pattern test  credit card number       true      var cb is master   cb mast pattern test  credit card number       true      var cb is amex   cb amex pattern test  credit card number       true      var isDisc   cb disc pattern test  credit card number       true      cb is amex   jQuery   credit card number text field   random id  mask  999999999999999     jQuery   credit card number text field   random id  mask  9999999999999999        var credit card number   jQuery   credit card number text field   random id  val        cb is amex   jQuery   credit card number text field   random id  mask  9999 9999 9999 999     jQuery   credit card number text field   random id  mask  9999 9999 9999 9999         if  cb is visa    cb is master    cb is amex    isDisc            if  cb is visa    cb is master    isDisc                var sum   0              for  var i   0  i  lt  credit card number length  i                      var intVal   parseInt credit card number substr i  1                    if  i   2    0                        intVal    2                      if  intVal  gt  9                                                intVal   1    intVal   10                                                           sum    intVal                            var contact bank check validity    sum   10     0   true   false                     jQuery   text appear after counter credit card   random id  css  display   none            if  cb is visa   amp  amp  contact bank check validity               jQuery   credit card number text field   random id  css   background-image   url  lt  php echo plugins url  assets global img cc-visa svg   dirname   FILE        gt     background-repeat   no-repeat   padding-left   40px    padding-bottom   5px               else if  cb is master  amp  amp  contact bank check validity                 jQuery   credit card number text field   random id  css   background-image   url  lt  php echo plugins url  assets global img cc-mastercard svg   dirname   FILE        gt     background-repeat   no-repeat   padding-left   40px    padding-bottom   5px               else if  cb is amex               jQuery   credit card number text field   random id  unmask               jQuery   credit card number text field   random id  mask  9999 9999 9999 999               jQuery   credit card number text field   random id  css   background-image   url  lt  php echo plugins url  assets global img cc-amex svg   dirname   FILE        gt     background-repeat   no-repeat   padding-left   40px   padding-bottom   5px               else if  isDisc  amp  amp  contact bank check validity                 jQuery   credit card number text field   random id  css   background-image   url  lt  php echo plugins url  assets global img cc-discover svg   dirname   FILE        gt     background-repeat   no-repeat   padding-left   40px   padding-bottom   5px               else               jQuery   credit card number text field   random id  css   background-image   url  lt  php echo plugins url  assets global img credit-card svg   dirname   FILE        gt     background-repeat   no-repeat   padding-left   40px    padding-bottom   5px                 jQuery   text appear after counter credit card   random id  css  display   block   html  lt  php echo json encode  cb invalid card number    gt   addClass  field label                        else           jQuery   credit card number text field   random id  css   background-image   url  lt  php echo plugins url  assets global img credit-card svg   dirname   FILE        gt     background-repeat   no-repeat   padding-left   40px    padding-bottom   5px             jQuery   text appear after counter credit card   random id  css  display   block   html  lt  php echo json encode  cb invalid card number    gt   addClass  field label

User · Answer

You should really use  test     if   re16digit test document myform CreditCardNumber value       alert  Please             You should also look around for implementations of  one or more of  the card number checksum algorithms  They re very simple

User · Answer

Maybe have a look at this solution  https   codepen io quinlo pen YONMEa    pop in the appropriate card icon when detected cardnumber mask on  accept   function          console log cardnumber mask masked currentMask cardtype       switch  cardnumber mask masked currentMask cardtype            case  american express               ccicon innerHTML   amex              ccsingle innerHTML   amex single              swapColor  green                break          case  visa               ccicon innerHTML   visa              ccsingle innerHTML   visa single              swapColor  lime                break          case  diners               ccicon innerHTML   diners              ccsingle innerHTML   diners single              swapColor  orange                break          case  discover               ccicon innerHTML   discover              ccsingle innerHTML   discover single              swapColor  purple                break          case   jcb      jcb15                ccicon innerHTML   jcb              ccsingle innerHTML   jcb single              swapColor  red                break          case  maestro               ccicon innerHTML   maestro              ccsingle innerHTML   maestro single              swapColor  yellow                break          case  mastercard               ccicon innerHTML   mastercard              ccsingle innerHTML   mastercard single              swapColor  lightblue                 break          case  unionpay               ccicon innerHTML   unionpay              ccsingle innerHTML   unionpay single              swapColor  cyan                break          default              ccicon innerHTML                   ccsingle innerHTML                   swapColor  grey                break

User · Answer

I m sure all of these algorithms are great  but you cannot verify that a card number is valid just by running an algorithm on it   Algorithms make sure the format is correct and its checksums are valid  However  they do not guarantee the bank will accept the card    For that  you need to actually pass the card number to your bank for approval

User · Answer

Find the source code from github for credit card validiations   it will work 100

User · Answer

Maybe you should take a look here  http   en wikipedia org wiki Luhn algorithm  Here is Java snippet which validates a credit card number which should be easy enough to convert to JavaScript     public static boolean isValidCC String number         final int     sumTable     0 1 2 3 4 5 6 7 8 9   0 2 4 6 8 1 3 5 7 9        int sum   0  flip   0       for  int i   number length   - 1  i  gt   0  i--          sum    sumTable flip    amp  0x1  Character digit number charAt i   10              return sum   10    0

User · Answer

These are my two cents   Note  1  this is not a perfect validation method  but it is OK for my needs  Note  2  IIN ranges can be changed  and will be   so it is a good idea to check this link to be sure that we are up to date   function validateCCNum ccnum        var ccCheckRegExp       d s-        var isValid    ccCheckRegExp test ccnum       var i       if  isValid            var cardNumbersOnly   ccnum replace    s-  g              var cardNumberLength   cardNumbersOnly length           var arrCheckTypes     visa    mastercard    amex    discover    dinners    jcb            for i 0  i lt arrCheckTypes length  i                  var lengthIsValid   false              var prefixIsValid   false              var prefixRegExp               switch  arrCheckTypes i                     case  mastercard                       lengthIsValid    cardNumberLength     16                       prefixRegExp    5 1-5  0-9   2   2 2-9   0  2 3-9   3-6  22 1-9  7 0-1  72 0    d                        break                   case  visa                       lengthIsValid    cardNumberLength     16    cardNumberLength     13                       prefixRegExp     4                       break                   case  amex                       lengthIsValid    cardNumberLength     15                       prefixRegExp     3  47                         break                   case  discover                       lengthIsValid    cardNumberLength     15    cardNumberLength     16                       prefixRegExp      6011 5                        break                   case  dinners                       lengthIsValid    cardNumberLength     14                       prefixRegExp      300 301 302 303 304 305 36 38                        break                   case  jcb                       lengthIsValid    cardNumberLength     15    cardNumberLength     16                       prefixRegExp      2131 1800 35                        break                   default                      prefixRegExp                                    prefixIsValid   prefixRegExp test cardNumbersOnly               isValid   prefixIsValid  amp  amp  lengthIsValid                  Check if we found a correct one             if isValid                    break                                     if   isValid            return false                Remove all dashes for the checksum checks to eliminate negative numbers     ccnum   ccnum replace    s-  g             Checksum   Mod 10          Add even digits in even length strings or odd digits in odd length strings      var checksum   0      for  i    2 -  ccnum length   2    i  lt   ccnum length  i    2            checksum    parseInt ccnum charAt i - 1                  Analyze odd digits in even length strings or even digits in odd length strings      for  i    ccnum length   2    1  i  lt  ccnum length  i    2            var digit   parseInt ccnum charAt i - 1     2          if  digit  lt  10                checksum    digit            else               checksum     digit - 9                        return  checksum   10      0      Thanks to  Peter Mortensen for the comment

[javascript] How to validate a credit card number

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