Keys received together
If every held key appears, that exact combination reached the browser successfully.
Simultaneous key test
Keyboard rollover & ghosting test.
Hold the combinations you actually use and see whether every key reaches the browser at the same time.
Keyboard rollover and ghosting tester
Hold a real shortcut or game combination. Every key the browser receives appears below.
0keys held now
W + A + Shift + SpaceTry it
W + D + Ctrl + SpaceTry it
↑ + ← + SpaceTry it
Interpretation
Test combinations, not marketing labels.
A peak count is useful, but it does not prove that every combination of that size works. Matrix limitations often affect particular clusters of keys.
A key goes missing
If a pressed key disappears only in a particular combination, the keyboard may be blocking that matrix path.
An extra key appears
True ghosting creates an unpressed key. Modern keyboards more often block a key instead of reporting a false one.
How to run a meaningful test
- Choose combinations from your games, shortcuts, or accessibility workflow.
- Hold the keys together for a second and verify every label appears.
- Repeat the same combination several times and reverse the order of key presses.
- Compare another USB port or computer before concluding the keyboard is defective.
Read the full keyboard rollover and ghosting guide for matrix limitations, terminology, and troubleshooting.
Browser limitation: operating-system shortcuts may be intercepted before this page sees them. That is not evidence of a keyboard failure.