I don't understand why firefox makes it so difficult to stop websites from autoplaying videos. Case in point: fox news and fox business news web sites. They have that stupid pop up when you scroll down the page, so if the main video is blocked the popup ignores it and starts playing. The preferences->autoplay doesn't allow you to enter a site to block and clicking on the lock on the url bar doesn't work because the permissions line isn't clickable, so we are left to resort to about:config which also fails to block these sites. This is very frustrating and if anything will drive me to another browser its stuff like this.