getCreditCardType

cc-verification.js

// automatic creditcard detection  @Seth Malaki `Electric Jesus` (c) 2012
// returns credit type on success. returns null if either unsupported or fails checksum validation (Luhn algorithm).

function getCreditCardType(accountNumber, doVerify)
{  
	var typeKey = null;
	// inspect account number, no dashes
	var creditCardInspectors = {
		VI : /^4\d{3}-?\d{4}-?\d{4}-?\d{4}$/,		// Visa
		MC : /^5[1-5][0-9]{14}$/,					// Mastercard
		AE : /^3[47][0-9]{13}$/,					// Amex
		DI : /^6(?:011|5[0-9]{2})[0-9]{12}$/,		// Discover
		DC : /^3(?:0[0-5]|[68][0-9])[0-9]{11}$/,	// Diner's Club
		JC : /^(?:2131|1800|35\d{3})\d{11}$/		// JCB
	};
	
	jQuery.each(creditCardInspectors, function(key, value) {
		//console.log(key);
		//console.log(value.test(accountNumber));
	
		if(value.test(accountNumber) == true) {			
			if(doVerify != true) {
				typeKey = key; return;
			}
			else {	// Luhn algorithm
				var checksum = 0;
				for (var i=(2-(accountNumber.length % 2)); i<=accountNumber.length; i+=2) {
					checksum += parseInt(accountNumber.charAt(i-1));
				}
				for (var i=(accountNumber.length % 2) + 1; i<accountNumber.length; i+=2) {
					var digit = parseInt(accountNumber.charAt(i-1)) * 2;
					if (digit < 10) { checksum += digit; } else { checksum += (digit-9); }
				}
				if ((checksum % 10) == 0) { typeKey = key; return; } else { return null; }
				
			}
		}	
	});
	//not found
	return typeKey;
}