[Senji]

Maybe tabs not currently being viewed should have their JS throttled? Is this an option in FF yet?

[reitanqild]

I use Suspend Tab.

Earlier this year I realized a major offender was Google search and search results pages which would spin up a core more than once a minute.

This explained to me at least why it was still hogging cpu even with ad blocker.

[nicoburns]

Not yet, but they're working on it:

https://billmccloskey.wordpress.com/2016/10/27/mozillas-quan...

and a preliminary version is in Chrome 56:

https://www.chromestatus.com/features/5701844080787456

[drkstr]

Use requestAnimationFrame instead of setTimeout to get a throttled heartbeat.