I am working on a game which is nowhere near completion yet, so I cannot give you a running example, however, I can say what I am doing.
I have 5 cropped sections over the screen, each showing a different representation of the scene. Eg the user's main view, a mini-map showing the user's relation to others, etc
There are several text areas giving the user important info. About 50 bits of text which need to be aligned, due to them needing to be in columns.
I only have about 30 images in each scene that are moving.
In the wonderful chrome I am getting 60fps.
In edge I am getting 45fps, but it has the known keyboard input issue which might put some users off using edge.
However in Firefox I am getting a terrible 6fps.
Has anyone experienced such a thing before? Is there something in Firefox that needs to be turned on or something?
UPDATE: I have literally removed most things except the very base animation (24 small 25x25 pixel sprites and 2 large 2000x2000 background sprites) and I am still only getting 10fps on firefox. There must be a firefox setting that is not right on my machine, or I am setting things up incorrectly somehow that firefox does not like.