function cc_checker($card_number) // Remove any non-digit characters $card_number = preg_replace('/\D/', '', $card_number);
: Use regular expressions to identify the card brand (Visa, Mastercard, etc.) based on the leading digits. Visa : Starts with 4; length 13 or 16. Mastercard : Starts with 51–55; length 16. American Express : Starts with 34 or 37; length 15.
<form method="post" enctype="multipart/form-data"> <input type="file" name="cc_list" accept=".txt"> <input type="text" name="gateway_url" placeholder="Payment gateway endpoint"> <input type="submit"> </form>
