Scroll Wheel Test
Check vertical and horizontal scroll wheel input, direction, step counts, and delta values in real time.
Test interface
Your browser may ask for permission after you press Start.How to use this tool
- Place the pointer over the scroll pad.
- Scroll up, then down, and watch the direction and step counters change.
- Tilt the wheel sideways or use a horizontal gesture if your device supports it.
- Use Reset to clear the counters before testing another direction.
Advertisement
Technical explanation
The page listens for wheel events and reads deltaX, deltaY, and deltaMode. Positive deltaY usually means scrolling down. deltaMode indicates pixel, line, or page units, which is why raw values differ between browsers and devices.
A single wheel notch can generate several events, especially with smooth scrolling or high-resolution wheels. The step counter therefore shows events, not physical detents. Browsers may also apply their own smooth-scroll animation after the event.
Troubleshooting
Scrolling does nothing
Click the pad first so it has focus, then scroll with the pointer inside it. Check that the wheel is not locked in software.
Direction is reversed
Operating-system or application settings may invert scrolling. Compare with another application before treating it as a hardware fault.
One notch counts many steps
Smooth scrolling and high-resolution wheels emit multiple events per detent. This is normal.
Horizontal scrolling is missing
Many mice have no tilt wheel. Use a trackpad gesture or a mouse that supports horizontal scrolling.
Related tools
Frequently asked questions
Advertisement