[whatwg] JSONRequest

[Douglas Crockford]

> The cache rules are unworkable, please remove these and use standard
> HTTP methods for suggesting the cacheability of a resource, forcing
> them to be uncacheable is unworkable w.r.t. to proxy caches and
> extremely unwelcome within the browser.

   Applications must not cache responses to a POST request because the
   application has no way of knowing that the server would return an
   equivalent response on some future request.