It often happens that I just want to browse some website, but the site has broken encryption (like an invalid certificate, an expired certificate, a CA
that is down and so on) and the browser refuses to display the page.
This is much appreciated when dealing with things like online banking, but if I have no intention of doing anything privacy-sensitive (like signing in or sending personal information), I just find this as a hindrance.
http://... would allow you to establish a plain old unencrypted connection in the past, but nowadays most sites automatically redirect you to a secured connection. Some of these errors can be circumvented by forcing the browser to accept a certificate exception, but this is unwieldy and can become a security risk if I forget to remove the dubious cert afterwards.
Is there a way to force a browser to only accept plaintext connections, only for a single misbehaving domain, and preferably for just a single session? I personally use Firefox, but details about other browsers are welcome too.