I think something like that might be feasible in the future with things like web bundles[1] and content security policy[2]. In theory you could have a site load

I think something like that might be feasible in the future with things like web bundles[1] and content security policy[2]. In theory you could have a site loaded as a bundle and a CSP that blocks everything not loaded through the bundle, effectively cutting off all network access. You'd probably also need some sort of Feature-Policy[3] that prohibits access to any form of persistent storage so sites can't just save data until the next non-CSP-protected page load and transmit it then. [1]: https://wicg.github.io/webpackage/draft-yasskin-wpack-bundled-exchanges.html https://wicg.github.io/webpackage/draft-yasskin-wpack-bundle... [2]: https://developer.mozilla.org/en-US/docs/Web/HTTP/CSP https://developer.mozilla.org/en-US/docs/Web/HTTP/CSP [3]: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Feature-Policy https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Fe...