這裡JavaScript版的信用卡校驗代碼，采用了Luhn算法
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 function isValidCreditCard(type, ccnum) { if (type == "Visa") { // Visa: length 16, prefix 4, dashes optional. var re = /^4d{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; }