How to do frame-by-frame animation with javascript?

[oro_junestar]

I've got a pretty complicated idea; I want to make an interactable pet window with my cat character, Hope. I've split her into multiple parts to allow for interactions like petting her head, poking her eyes, or swapping her bandana.
This is how she looks on the site:

This is how she's arranged in the code:


My question is, how can I use scripts to move the individual parts to set positions in set timing?

I want to start with a tail wag animation like this: