you but there are some extra steps to take else the card may declined ny the merchant
read the following
Using Visa or American Express Gift Cards to Shop Online
One of the most asked gift card questions, particularly on Yahoo Answers is whether you can use a Visa or any other bank issued gift card (American Express, Discover, or MasterCard) to shop online. The answer is yes.
However, there are additional steps you have to take to prevent your card from being rejected by the merchant. The problem with using Visa (or any other bank issued) gift card online is that there is no verifiable name and address associated with the card. When buying things online, most merchants want your name and billing address to match the name and address you have on file with your card (credit, debit, or bank gift card) issuer.
Therefore, before you use your Visa or other bank issued gift card, call the merchant/financial institution that issued the card or go to their website and add your name and address to the card. This will ensure that when you use the card online, the name and address you provide to the merchant for billing will match the name and address on file for the card. Once you have registered your card, you can use it online just like you would use a regular credit card.