We already new Mozilla was working on an autoplay block as the company detailed the feature in a roadmap earlier this year. At the time the company promised a solution that “doesn’t break websites”. That latter statement is important. While autoplay ads can be annoying and sometimes dangerous, in many cases they are not. Some sites use them for advertising, which is fine. The worst these harmless enough videos do is shock you if the volume is mysteriously loud. However, some malicious popup autoplay videos will lock users down and force them to click something to leave. Often these clicks can lead to malware attacks. Of course, on a normal website this is not going to happen. If you get fried by a malicious autoplay video, It probably says more about the websites you visit.
— Dale Harvey (@daleharvey) July 21, 2018
More Control
Either way, in the latest Firefox Nightly Edition preview build (63.0a1) the browser has an option to turn off videos. Users can find the feature as a small pop-up that appears below the address bar. If you want a more sweeping block of autoplay videos, Firefox settings have been updated. Users can select to block all autoplaying media across the board. If selected, the individual pop-up option will no longer appear. It is worth remembering that this ability is only in preview at the moment. Mozilla is expected to roll out Firefox 63 at the end of October to all users.