Putting [validcard] into a template displays "T" or "F", depending on the value of the number in accountNum. If the accountNum is a legitimate credit card number for the specified card type (according to the algorithm used to create such numbers), then "T" indicates it is good. Conversely, "F" indicates it is bad. This does not call the bank to verify funds on the card -- it merely does a simple numeric checksum to verify the number is consistent with a credit card number, and not a randomly punched in string of numbers. You would use this tag to validate the credit card field on your order form BEFORE writing it to the shopping cart order file. If it evaluates to F, you can display an alert and ask the customer to please double-check the credit card before continuing.

Example:

[validcard accountNum=cardNumber&card=VISA+MC]

Parameter	Description
accountNum	(Required) The credit card number. Any extra spaces or non-numeric characters will be ignored.
card	(Optional) Set card to the names of the credit cards that are allowed, separated by space or +. Possible values are ALL, IGNORE, VISA, MC, AMEX, DISC, JCB, DINER. If not specified, then ALL cards are allowed. IGNORE tells it to always pass the card regardless of its checksum.