declare option output:method "html";
declare option output:html-version "5.0";
<select><option value="a" selected="selected">a</option>
<option value="b" bad="bad">b</option></select>

Result

<!DOCTYPE html>
<select>
  <option value="a">a</option>
  <option value="b" bad="bad">b</option>
</select>


Note bizzare vanishing of selected="selected". Seems to only happen only for option with selected="selected" for all html versions.

/Andy