[codegeek]

It helps to display the card type while you type because then I know that I am typing something reasonable and I know that I am not entering incorrectly. Of course, the entire card number could still be wrong which can only be validated by the server/backend processor but overall, displaying the type gives a level of "instant" comfort. It also gives users peace of mind that they system knows what they are doing. Think non technical users who don't understand the diff b/w client side vs server side validation. For them, it will be comfortable to see that the system interprets their card type which might give them more comfort. No data to back this up but just something I might think as a user.

[mrweasel]

I get your point, but to tell that a card is a VISA you just need to enter "4". I don't think it makes much of a difference really, just avoid showing in card type info and no one wonders.

It might be better to let the customer pick their card type, that you could also better inform them that you do not accept their card type.