Is there a W3C valid way to disable autocomplete in a HTML form?

Question

When using the xhtml1-transitional.dtd doctype, collecting a credit card number with the following HTML

Answer 1

I think there's a simpler way. Create a hidden input with a random name (via javascript) and set the username to that. Repeat with the password. This way your backend script knows exactly what the appropriate field name is, while keeping autocomplete in the dark.

I'm probably wrong, but it's just an idea.