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

if (document.getElementsByTagName) {
    var inputElements = document.getElementsByTagName("input");
    for (i=0; inputElements[i]; i++) {
        if (inputElements[i].className && (inputElements[i].className.indexOf("disableAutoComplete") != -1)) {
            inputElements[i].setAttribute("autocomplete","off");
        }
    }
}