I noticed we're using the following doctype:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
Which leads to validation errors due to our
autocomplete attributes. Why aren't we using the HTML 5 doctype below?
This doctype activates standards modes in old browsers but is valid for the HTML5 markup the SE sites are in fact using right now.