Non-SSL contents on SSL pages are blocked by default
Bug 834836 – Turn on pref to block mixed active content
Firefox 18 introduced preferences to block loading contents from non-SSL (http) sites on SSL (https) pages. One of those preferences, security.mixed_content.block_active_content is now enabled by default in order to enhance user security. That means insecure scripts, stylesheets, plug-in contents, inline frames, Web fonts and WebSockets are blocked on secure pages, and a notification is displayed instead. It will not block "display content" like images, videos or audio.
