Is there a W3C valid way to disable autocomplete in a HTML form? When using the xhtml1-transitional.dtd doctype, collecting a credit card number with the following HTML <input type="text" id="cardNumber" name="cardNumber" autocomplete='off'/> will flag a warning on the W3C validator:       there is no attribute "autocomplete". Is there a W3C / standards way to disable browser auto-complete on sensitive fields in a form? Answer: Here is a good article from the MDC which explains the problems (and solutions) to form autocompletion. Microsoft