Bank Cards vs. Credit Cards
If you have a choice, it is usually better to make online transactions with credit cards rather than bank cards.
Bank cards deduct funds directly out of your bank account and if someone steals that card number and drains your account you may be stuck with no money while you are sorting out the fraud claims with the bank. I have seen this happen before.
If you use a credit card and someone steals your credit card number, you still will have your cash in your bank account to live on while your sort out the fraud claims. Just make sure before you use your credit card that the credit card company provides protection against online fraud.