What the Keyboard Ghosting Test Measures
Rollover describes how many simultaneous keys a keyboard can report. Blocking means an intended key is not delivered in a combination; ghosting can mean an unexpected extra key appears.
A browser knows only the key events it receives. It cannot directly know which physical key you pressed if that event was blocked before delivery.
How to Use the Keyboard Ghosting Test
- 1Choose a preset combination or your own group of keys.
- 2Hold all intended keys together while the page is focused.
- 3Compare the highlighted observed codes with the keys you intended to hold.
- 4Release them, repeat, and try a different combination.
How to Interpret the Result
The maximum simultaneous number is a browser-observed count, not a certification of full NKRO. A preset mismatch may indicate blocking, but confirm your actual presses and repeat the run.
An unexpected code should be checked across runs before calling it possible ghosting. Auto-repeat must not increase the held-key count.
Rollover, Blocking and Possible Ghost Keys
Rollover describes how many keys can be reported at once for the combination you pressed. A preset shows the expected codes supplied by the test instructions and highlights those the browser receives. An intended key that fails to appear may be blocked somewhere before the page, but the page cannot independently verify that your finger pressed it.
An extra observed code can be useful evidence of possible ghosting, yet it may also reflect an accidental press or a layout mismatch. Release the keys completely, repeat the combination, and compare another preset. The maximum observed count from one combination does not certify all combinations or the keyboard's advertised NKRO capability.
Browser Limitations
Operating-system shortcuts, focus loss and browser handling can hide keys. The page cannot certify a keyboard's matrix or electrical rollover design. It reports observed key events and user-selected expectations.