Is valid credit card number
Checks if the value is a valid credit card number.
Checks whether the incoming value is a valid credit card number. A value passes when it looks like a card number from one of the major brands (Visa, Mastercard, American Express, Diners Club, Discover, or JCB) and its check digit adds up correctly, so a typo in a single digit is caught. Use this to confirm a card field holds a plausible number before you send it on, or to route records with a missing or malformed number down a different path. The check only looks at the format of the number itself; it does not contact any payment provider or confirm the card actually exists. Supply the number as digits with no spaces or dashes.