What happens to a an offline cached page when an error page is returned?

I'm running a web app hosted on heroku, and b/c of an outage at amazon it's been out all day long.

If I 开发者_高级运维make a cache manifest to specify that a page should be cached, the page would be served from the cache when the user is offline. But what happens when heroku serves an error page, or the page partially loads, but then times out?

Read this link: http://www.w3.org/TR/html5/offline.html

If the page is stored in the offline cache, it is served first before anything is downloaded. So if there is an error or timeout the browser simply does not update the offline cache.