I don't think you need a fancy javascript for that though... make that "Refresh The Porn" link a link to itself.. i assume it's a php script in there somewhere so link to
http://www.pf69-galleries.com/random-porn/ (and maybe add index.php there, though I think that might not work or do any good)
But if it is then each time bots will hit the page they'll see it differently - causing them to come back again...
(just check your bandwidth though - some like MSNBot have been known to kamikaze into a site like a blind bull, cranking it up)