focus-on: (element|selector set) [every (time)] [after (time)][, (element)...];
element/selector set = Element to be given focus. This should be a reference to one element only, or the first in a group, or a form. It accepts the following values:
- me, self, or this - focus on the target selector.
- Any valid CSS selector. If more than one element is in the list, the first found will be focused on only.
- first - If the target selector is a form, focus on the first element in the form.