There are many sources for credit card prefixes (as well as check digit algorithms) for validating credit cards. For example, http://en.wikipedia.org/wiki/Bank_card_number
I think as long as users are clear what cards you accept there is no need to ask. For me, it is almost always Amex that I have trouble with, so I check that Amex is listed before I get too far. I have never known a 'grown-up' MasterCard or Visa not to work. (My daughter has a teen-age version which is so badly supported by some sites and stores, which say they accept it and then don't, that she has actually lost her confidence in using it. Part of this is the bank's fault for changing the name of the thing so many times.) Regards, William Hudson Syntagm Ltd Design for Usability UK 01235-522859 World +44-1235-522859 US Toll Free 1-866-SYNTAGM mailto:[email protected] http://www.syntagm.co.uk skype:williamhudsonskype Syntagm is a limited company registered in England and Wales (1985). Registered number: 1895345. Registered office: 10 Oxford Road, Abingdon OX14 2DS. Confused about dates in interaction design? See our new study (free): http://www.syntagm.co.uk/design/datesstudy.htm 12 UK mobile phone e-commerce sites compared! Buy the report: http://www.syntagm.co.uk/design/uxbench.shtml Courses in card sorting and Ajax interaction design - Las Vegas and Berlin: http://www.nngroup.com/events/ > -----Original Message----- > From: [email protected] [mailto:discuss- > [email protected]] On Behalf Of Jared Spool > Sent: 28 September 2009 11:24 PM > To: Amy Jones > Cc: [email protected] > Subject: Re: [IxDA Discuss] Is there a good reason to require people to > idtheir credit card? ________________________________________________________________ Welcome to the Interaction Design Association (IxDA)! To post to this list ....... [email protected] Unsubscribe ................ http://www.ixda.org/unsubscribe List Guidelines ............ http://www.ixda.org/guidelines List Help .................. http://www.ixda.org/help
