Was running into problems with browser-based videos not playing in the background. This popped up as a suggestion and I tried it with some hesitation. But, lo and behold, this fixed the problem right away.

Sometimes works, sometimes doesn't

It plays in background, but often doesn't load the video in background.

Meh. More miss than hit

wow this works. thanks. Now I can turn on my phone display while m.youtube plays in BG