Skip Nav: Where do I send the focus to?

Hi,

I want to add a skip nav link.

I'll put the link at the top of HTML Inserts: Body Top:
then I'll put in some CSS to hide this link from users with good vision.

What I would like to know is if there is a way to send the focus to .post-bodycopy, or where I could put something in index.php so I don't have to put something in every post/page?

Any thoughts?

-Bill