What this test checks
Test vertical and horizontal mouse-wheel events, direction changes and possible repeated or reversed scroll input.
InputAnalyzer processes test events locally and does not upload your raw inputs or result values.
How to run the test
Focus the scroll target
Move the pointer over the test area so the page can separate test input from ordinary page scrolling.
Scroll one direction at a time
Use several slow upward steps, pause, then use the same number of downward steps.
Test horizontal input
If your wheel, trackpad or modifier supports it, repeat the check from left to right.
How to read the result
Observed signals, not artificial certainty.
Consistent direction
Events follow the intended direction without isolated reversals during a controlled sequence.
Possible wheel bounce
Repeatable opposite-direction events or unexplained bursts can indicate irregular input, driver processing or gesture momentum.
What this test cannot prove
What the browser cannot see
- Browsers report wheel deltas in pixels, lines or pages, so magnitude is not directly comparable across systems.
- Trackpad momentum, acceleration and accessibility settings can continue or reshape a scroll gesture.
- Results are browser-based estimates, not a physical hardware diagnosis.
Useful next tests
Frequently asked questions
Short answers before you test again
Why are my scroll values not whole steps?
High-resolution wheels and trackpads often report small pixel deltas. This is normal and differs from a notched wheel.
What can cause a brief reversed scroll?
Wheel bounce is one possibility, but finger movement, gesture momentum and driver software can produce the same observation.