Comments on: Using the Luhn algorithm to validate credit cards

By: Andy best

Andy best — Mon, 23 May 2011 09:25:45 +0000

I read and finally found granded resolution to my desire but it was too much for me please try to indicate go to the right answer for us in stead off polongment

By: Israel

Israel — Tue, 04 Jan 2011 11:17:03 +0000

The shortest version I’ve found, for Luhn check:

// Luhn algorithm validator, by Avraham Plotnitzky. (vzckakh at gmail)
String.prototype.luhnCheck = function()
{
var luhnArr = [0, 2, 4, 6, 8, 1, 3, 5, 7, 9], sum = 0;
this.replace(/\D+/g,”").replace(/[\d]/g, function(c, p1, offset){
sum += ((offset.length-p1)%2)? parseInt(c) : luhnArr[parseInt(c)];
});
return (sum%10 == 0) && (sum > 0);
};

By: gabriel

gabriel — Thu, 23 Dec 2010 15:12:16 +0000

i need a valid credit card number,expire date,cvv,i kindly beg,i will not use it for anything bad o crime.

By: phygg

phygg — Tue, 11 May 2010 16:54:02 +0000

I appreciate the other ways for validating credit cards you have posted. But, I’m in need of the regex versions that were written by the author whom originally posted, you know the “inspiration” for this blog post.
I’m using regular expressions to filter email content. they don’t allow for other types of formatting or scripts.
Do you have the original post, i noticed that the link was broken.
Thanks
Phygg

By: Rad

Rad — Mon, 12 Oct 2009 18:05:56 +0000

I’ve always used 4111-1111-1111-1111 this is a valid visa test number..

By: superjason

superjason — Tue, 21 Oct 2008 16:24:46 +0000

Johansen, talk to your merchant account. They can give you test credit card information. Or consult the API documentation for the merchant.

By: johansen

johansen — Tue, 21 Oct 2008 13:11:00 +0000

i need a valid credit card number,expire date,cvv,i kindly beg,i will not use it for anything bad o crime.

By: Greg Jorgensen

Greg Jorgensen — Wed, 16 Apr 2008 21:18:00 +0000

There are a couple of reasons I can think of to use a regex before or along with the Luhn validation: The regex checks can figure out what kind of card the number is from (Visa, Mastercard, AMEX, etc.), and it can make sure the card number is the correct length for the card type.

If my ecommerce site doesn’t accept Discover, for example, it’s better to figure that out and tell the user. The number they entered may be a valid card number (it passes the Luhn check) but my payment processor doesn’t let me accept it.

Not all credit card numbers are the same length. It’s possible for someone to enter a number that passes the Luhn test but is not a valid card number.

Use regext + Luhn if you site isn’t doing real-time credit card authorizations, or if your payment processor is slow, or penalizes you for attempting to auth a bad card number, or if you want to give my customers better messages about what went wrong.

I have a long article about the Luhn algorithm and checking credit card numbers in Javascript here.