Just open a new window and leave the tab with the video on top of that window. (...

Nursie · on March 21, 2020

Doesn't work on mobiles.

masswerk · on March 22, 2020

Then you are doomed. ;-) (On mobile, it's your browser anyway that mutes any not currently on top and visible web sources, without any "help" by the particular website.)

Nursie · on March 29, 2020

I know this is an old topic now, but that's not true. I've installed a firefox plugin that disables the visibility API. Result - now youtube in a firefox tab keeps playing even with my screen locked.

It is most definitely the page doing the muting.