An upcoming release of Firefox will prevent non-SSL non-display content loading on SSL pages.
One of the lingering "why do they do that" features of the internet is finally, albiet slowly, becoming a thing of the past: The loading of non-secured content on a secured page.
On May 23, Firefox 23 will be released, and by default, it will block any non-SSL content loading on an SSL page.
This means that any scripts, CSS, plugin contents, inline frames, fonts, or WebSockets that are loading with http instead of via https protocol will spark a notification to life.
Avoiding this mechanism will be images, video, or audio.
Which is good news for the unseemly side of the internet, in that it will still be possible to attack "secured" web pages via display content.
For the rest of us, it's means that if you run an SSL site, make sure it loads all of its content from an appropriate protocol.
By switching the security.mixed_content.block_active_content option in a copy of Firefox later than version 18, you can have it operate like Firefox 23 by default. For those that do not keep up with Firefox release numbers (who does?), that means the latest version of Firefox, 20, has it.