The layerX and layerY solutions will break in IE9 when run in an (i)frame.
IE9 pretends to support layerX and layerY but gives wholefully wrong values when run from a document inside an (i)frame. Somehow the offset off this document relative to its parent is added to the total.
-- Martinj Otto 2017-10-21 06:20 UTC
Ah. Well, I don’t use such, which is probably why Square Shooter is reported to work in IE9. I seem to remember Firefox having a similar issue until I learned to set the canvas element to Position: relative. Good to know!
-- Felix 2017-10-21 06:21 UTC