This add-on is very small and has one simple thing it does. It modifies all requests so that they will always load from cache even on reload, revalidate headers or new browser session, no calls to the internet is made IF the ressource is in the cache already. It effectively replaces all 30X requests to 200 cached requests. New resources/websites are still loaded from the web.
This has 3 advantages:
- Less bandwidth used.
- Almost no CDN tracking anymore, Google & co saves its scripts till 2034 in your cache but always revalidates which makes no sense since the libraries don't change. When enabled jQuery & co will just be read from the cache.
- Faster pageloads (gain depends on the website, but its quite noticeable).
You have 3 states of the addon which are super easy and quick to switch to
Click the add-on button
Left click
Turn on forced cache loading for everything BUT html, xhtml, aspx and xml (this ensures that websites are updated for 99% of the web at least).
THIS IS THE STANDARD MODE, I always leave this on and never had problems (people reported problems with Flash but i don't use Flash so it doesn't matter to me)!
MiddleClick or Ctrl + left click:
Power Mode ... load everything from cache!
Very fast, but forums, live updating sites have might have problems updating their content.
YouTube comments don't update in this mode, but Facebook stream and Google Images works for example. It depends on how the website is made.
Very fast for all static sites like Wikipedia, MDN or other text based information and all sites with lots of big image elements and stuff, like a combination of offline mode and online mode. Great for working in areas with low internet reception or on the go (train , bus, etc).
Right click:
Disable addon functionality , everything is normal again.
Comments and Reviews
Users may try to set chrome://flags/#back-forward-cache to "Enabled force caching all pages (experimental)" with Chromium and derivatives.
"Show Saved Copy" button from 2013 is gone with latest versions of Chromium and derivatives.
https://addyosmani.com/blog/offline-mode-chrome
https://www.androidpolice.com/2015/05/20/tip-turn-on-this-chrome-dev-flag-to-enable-show-saved-copy-button-and-load-cached-pages-when-offline