Talking about "memory usage per tab" doesn't make much sense unless you talk about what's in the tabs. It's rather like talking about "memory usage per applicat

Talking about "memory usage per tab" doesn't make much sense unless you talk about what's in the tabs. It's rather like talking about "memory usage per application" on your desktop and not mentioning whether the application is ed or OpenOffice. Suspending JS execution in invisible tabs seems highly unlikely to be web-compatible; you wouldn't want YouTube or Spotify to stop playing just because you focused a different tab. On the other hand, with technologies like requestAnimationFrame, we can make it possible for well designed applications to work well when in the background.