Not unless the site sends the CSP header to tell it to upgrade to https: https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Content-Security-Po

Not unless the site sends the CSP header to tell it to upgrade to https: https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Content-Security-Policy/upgrade-insecure-requests https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/... A client side option to force https might still be useful though. But I can imagine at least some enterprise webapp that would die horribly if you tried this.