Google Answers JavaScript Around Pre-Rendering, Crawl Budget and More

In this episode of Ask Google Webmasters, John is joined again by Martin Splitt, Developer Advocate at Google, to discuss Javascript & SEO.

• When using Rails Asset Pipeline for caching what status code do we give the old asset? Googlebot crawls these stale assets which we currently have 404’d. Do we 410 instead or keep the old assets alive for a couple of months? It’s killing our crawl budget?  (0:43)
• In prerendering can we replace or skip irrelevant elements? I.e. svg bar graphs generated by JS? (2:19)
• If your site has a chat function that rewrites the title tag for notifications to the visitor, how do you or the app supplier prevent Google from indexing the JS rewritten version of the title tag?  (3:18)
• In prerendering: can still be JS inside? JS that generates minor content layout changes, but not AJAX requests.  (4:00)
• Will pre-rendering or dynamic rendering ever go away?  (5:10)