Mouse Scroll Test
Check whether browser wheel events arrive in the direction you expect.
Mouse Scroll Test
Scroll vertically, then try a sideways two-finger trackpad gesture or a tilt wheel if your device supports it.
Counts are browser wheel events, not physical wheel notches. Left/Right reflect the browser-reported horizontal delta; natural-scrolling settings can make the physical gesture feel inverted.
How to test scrolling
Scroll steadily in one direction inside the test area, then reverse. The recent direction strip makes unexpected opposite events easy to spot without declaring a hardware verdict.
If your scroll wheel jumps or stops registering
A steady scroll can help you reproduce missing browser events or unexpected opposite-direction events. Those observations do not by themselves prove a hardware fault, and wheel events can also come from a trackpad or another scrolling device rather than a physical mouse wheel.