Are Web page animations mostly done in JS or CSS?

Question

From my understanding JS animates an object that is created using CSS, is this correct?

Answer 1

mostly Javascript. But some sorts of animations can also be done by CSS.

check out on my codes, the mario Jumping and the loading animation, are done only by CSS.

Answer 2

No. Css is descriptive language, js is scripting/programming language that manipulates elements that are described by css.