JavaScript for credit card verification, javascript for credit card

JavaScript for credit card verification, javascript for credit card

This document describes how to verify credit card using JavaScript. Share it with you for your reference. The specific analysis is as follows:

Here, the JavaScript version of the credit card verification code uses the Luhn Algorithm

function isValidCreditCard(type, ccnum) {  if (type == "Visa") {   // Visa: length 16, prefix 4, dashes optional.   var re = /^4\d{3}-?\d{4}-?\d{4}-?\d{4}$/;  } else if (type == "MC") {   // Mastercard: length 16, prefix 51-55, dashes optional.   var re = /^5[1-5]\d{2}-?\d{4}-?\d{4}-?\d{4}$/;  } else if (type == "Disc") {   // Discover: length 16, prefix 6011, dashes optional.   var re = /^6011-?\d{4}-?\d{4}-?\d{4}$/;  } else if (type == "AmEx") {   // American Express: length 15, prefix 34 or 37.   var re = /^3[4,7]\d{13}$/;  } else if (type == "Diners") {   // Diners: length 14, prefix 30, 36, or 38.   var re = /^3[0,6,8]\d{12}$/;  }  if (!re.test(ccnum)) return false;  // Remove all dashes for the checksum   //checks to eliminate negative numbers  ccnum = ccnum.split("-").join("");  // Checksum ("Mod 10")  // Add even digits in even length strings   //or odd digits in odd length strings.  var checksum = 0;  for (var i=(2-(ccnum.length % 2)); i<=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 (var i=(ccnum.length % 2) + 1; i<ccnum.length; i+=2) {   var digit = parseInt(ccnum.charAt(i-1)) * 2;   if (digit < 10) { checksum += digit; }   else { checksum += (digit-9); }  }  if ((checksum % 10) == 0) return true; else return false;}

I hope this article will help you design javascript programs.