How to turn off autoplay in Mozilla Firefox

March 19, 2019

Firefox 66 has been released, and with the new version comes a most glorious feature: the blocking of autoplay content. This is a feature I have wanted forever, and am so happy it's now live. Now I can never leave Firefox.

To enable this feature:

Update Firefox (select Menu > Help > About Firefox, then restart browser).
Enter about:preferences#privacy in the address bar.
Scroll to the Permissions section and then tick the check box for Block websites from automatically playing sound.