Differntiate the type of card like credit or debit card

Unfortunately, there's no easy way to distinguish between debit and credit cards from the card number.

You just have to know (for a given issuer) which ranges of numbers represent debit and credit cards.

There's a useful list here on Wikipedia:

http://en.wikipedia.org/wiki/List_of_Issuer_Identification_Numbers

but, as you'll see, trying to devise a single regular expression to make this determination would be impractical.