All Credit Card and CCV2 fields should have "autocomplete" attribute set to "off"

Everywhere credit card information is collected there should be an attribute for "autocomplete" = "off". This keeps the browser from auto-completing or (more importantly) storing credit card numbers in the browser cache to begin with.

http://www.petefreitag.com/item/481.cfm
http://stackoverflow.com/questions/582244/is-there-a-w3c-valid-way-to-di...