Select your credit card and enter the credit card number:
/dashes, slashes, spaces, etc. are now allowed!/
Visa    American Express
MasterCard   Novus
 
Check result:

Version 2.0: Release notes.
Different credit cards are now "accepted". Dashes, slashes, etc. are now ignored!

General Information.
The algorithm was taken from the Perl script Credit Card Verifier, which was originally posted in the Matt's Script Archive.

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