As it stands, there is no ‘autocomplete off’ attribute in CSS. However, html has an easy code for this:
<input type="text" id="foo" value="bar" autocomplete="off" />
If you’re looking for a site-wide effector, an easy one would be to simply have a js function to run through all ‘input’ s and add this tag, or look for the corresponding css class / id.
The autocomplete attribute works fine in Chrome and Firefox (!), but see also Is there a W3C valid way to disable autocomplete in a HTML form?