I\'m looking for ways to prevent indexing of parts of a page. Specifically, comments on a page, since they weigh up entries a lot based on what users have written. This make
I would go with your JavaScript option. It has two advantages:
1) bots don't see it
2) it would speed up your page load time (load the comments asynchronously and unobtrusively, e.g. via jQuery) ... page load times have a much underrated positive effect on your search rankings