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JavaScript's method of randomly generating credit card Numbers

  • 2020-05-27 04:14:02
  • OfStack

This article illustrates an example of how JavaScript randomly generates credit card Numbers. Share with you for your reference. The specific analysis is as follows:

This JS code randomly generates the credit card number according to the rule of credit card number generation. It can be verified and used for reference only. Please do not use it for illegal purposes, or you will be responsible for the consequences. 


var visaPrefixList = new Array(
 "4539",
 "4556",
 "4916",
 "4532",
 "4929",
 "40240071",
 "4485",
 "4716",
 "4"
);
var mastercardPrefixList = new Array(
 "51",
 "52",
 "53",
 "54",
 "55"
);
var amexPrefixList = new Array(
 "34",
 "37"
);
var discoverPrefixList = new Array("6011");
var dinersPrefixList = new Array(
 "300",
 "301",
 "302",
 "303",
 "36",
 "38"
);
var enRoutePrefixList = new Array(
 "2014",
 "2149"
);
var jcbPrefixList = new Array(
 "35"
);
var voyagerPrefixList = new Array("8699");
function strrev(str) {
  if (!str) return '';
  var revstr='';
  for (i = str.length-1; i>=0; i--)
   revstr+=str.charAt(i)
  return revstr;
}
/*
'prefix' is the start of the CC number as a string, 
any number of digits.
'length' is the length of the CC number to generate. 
Typically 13 or 16
*/
function completed_number(prefix, length) {
 var ccnumber = prefix;
 // generate digits
 while ( ccnumber.length < (length - 1) ) {
  ccnumber += Math.floor(Math.random()*10);
 }
 // reverse number and convert to int
 var reversedCCnumberString = strrev( ccnumber );
 var reversedCCnumber = new Array();
 for ( var i=0; i < reversedCCnumberString.length; i++ ) {
  reversedCCnumber[i] = parseInt(reversedCCnumberString.charAt(i));
 }
 // calculate sum
 var sum = 0;
 var pos = 0;
 while ( pos < length - 1 ) {
  odd = reversedCCnumber[ pos ] * 2;
  if ( odd > 9 ) {
   odd -= 9;
  }
  sum += odd;
  if ( pos != (length - 2) ) {
 
   sum += reversedCCnumber[ pos +1 ];
  }
  pos += 2;
 }
 // calculate check digit
 var checkdigit = ((Math.floor(sum/10)+1)*10-sum)%10;
 ccnumber += checkdigit;
 return ccnumber;
}
function credit_card_number(prefixList, length, howMany) {
 var result = new Array();
 for (var i = 0; i < howMany; i++) {
  var randomArrayIndex = Math.floor(Math.random() * 
 prefixList.length);
  var ccnumber = prefixList[ randomArrayIndex ];
  result.push( completed_number(ccnumber, length) );
 }
 return result;
}

Call method:

Save the above code as the gencc.js file 


<html>
<head>
<script src="gencc.js" type="text/javascript"></script>
</head>
<body>
<h3>VISA:</h3>
<script>
var visa = credit_card_number(visaPrefixList, 16, 3);
document.write( visa );
</script>
<h3>Amex:</h3>
<script>
var amex = credit_card_number(amexPrefixList, 15, 3);
document.write( amex );
</script>
</body>
</html>

I hope this article is helpful for you to design javascript program.

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