Is it possible to use JavaScript to change the meta-tags of the page?

Question

If I put a div in the head and display:none, than use JavaScript to display it, will this work?

Edit:

I have stuff loaded in AJAX. And as my AJAX changes the

Answer 1

No, a div is a body element, not a head element

EDIT: Then the only thing SEs are going to get is the base HTML, not the ajax modified one.