Automatically change HTTP protocols to the secure HTTPS with Smart HTTPS addon
Smart HTTPS is a multi-browser addon that automatically requests websites over the secure https protocol instead of the insecure http. However, if a website does not support https, it reverts the address back to http, and automatically adds this exception to the memory. Next time, when you visit this address, it will load in http.
Please note, you can delete the exception from memory by visiting the addon options page. This way any time you visit a website, it will load it in https first, and if loading encounters an error, an exception will be added to the memory again. This is useful if you want to check http websites frequently to make sure that they have not changed their policies.