Firefox 66 shipping in 4 weeks will block media autoplay, defer timers during page load

We know it’s a bit late but we are getting back on track for the second release in 2019!

Firefox 66 Beta and Developer Edition have been available for the past few weeks. While there aren’t many changes because of the holiday season, your site might be affected by a couple of things including media autoplay blocking and setTimeout() deferring. The support for window.event and Event.returnValue, which was originally planned for Firefox 65, is also on the list.

Check out all our Firefox 66 compatibility notes to get prepared for the final version coming March 19.