What does this sentence mean?no CPU power or battery life is wasted drawing animations that are running in background tabs -

What does this sentence mean?no CPU power or battery life is wasted drawing animations that are running in background tabs -

context: first, draws animations visible user. means no cpu powerfulness or battery life wasted drawing animations running in background tabs, minimized windows, or otherwise hidden parts of page.

my first language not english, sentence means: animations running in background tabs, minimized windows, or otherwise hidden parts of page not drawed , no cpu powerfulness or battery life wasted

it means raf (request animation frame) loop does not run when window cannot seen , browser not update display of such hidden windows.

as consequence, animation updates (and other work) done within raf callback suspended until window 1 time 1 time again visible , raf resumes.

if timed logic must go on background window raf cannot reliably used because of optimization.

cpu battery requestanimationframe