Hold several keys at once and see which key events reach this browser. The page visualizes registered inputs; it cannot observe a key event that the keyboard, operating system or browser never delivers.
If an expected key does not light while you hold a combination, the browser did not receive that key event.
How to test: hold a combination you actually use, such as W + A + Space, then add another key. Watch which keys remain highlighted. Repeat the same combination several times. This can reveal a rollover limitation, but it does not prove the exact electrical cause inside the keyboard.
Ghosting asks whether a specific key combination is lost or misreported. Rollover asks how many simultaneous keys remain visible at once. Use the Key Rollover Test when the number of simultaneous registered keys is the main question.
Result guide
Hold the exact key combination you care about and watch which keys the browser continues to report. The useful result is whether a specific combination is fully visible, not a single overall score.
Geometry Dash normally needs only a small number of simultaneous inputs, but this visualizer can help when a custom setup or modifier combination appears to drop a key. Re-test the same combination several times before changing hardware.
A browser can show missing registered keys but cannot prove where the limitation occurs. Keyboard matrix design, firmware, the operating system and browser handling can all affect the observed combination.
