Created
February 1, 2012 06:34
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CreditCard Validation using Javascript
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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; | |
} |
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