Paul Irish made something similar. A jQuery plugin that used localStorage to cache ajax responses.<p><a href="https://github.com/paulirish/jquery-ajax-localstorage-cache" rel="nofollow">https://github.com/paulirish/jquery-ajax-localstorage-cache</a>
Looks like an open-source version of Cloudflare's Rocket Loader, but without the source file concatenation. Still, we should produce something open-source for these.