Keyboard Tester
Use this keyboard tester to check whether your browser receives each physical key on a laptop, desktop keyboard or external USB/Bluetooth board. Press keys and watch them light up live, with the physical event.code, produced event.key, key location, repeat events, rollover peak and possible stuck-key warnings shown locally in the page.
How to test a keyboard
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1
Choose the layout view
Pick ANSI, ISO or compact so the on-screen grid roughly matches the keyboard you are checking. The browser still reports physical key codes even if your language layout prints different characters.
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2
Start the test and press keys
Click Start test, keep the tab focused and press each key. Keys turn blue while held, green after release and amber if they stay held beyond the stuck-key warning time.
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3
Read the diagnostics
Use the event log, rollover peak, repeat count and held-key list to spot missing key events, repeated input, modifier location issues or combinations that your keyboard does not report together.
What a browser keyboard test can show
Browser keyboard events expose two useful values in modern desktop browsers. event.code identifies the physical key position, such as KeyQ, Space, NumpadEnter or ShiftLeft, where the browser supports it. event.key is the value produced by the current keyboard layout, so the same physical key can report a different character on QWERTY, AZERTY, QWERTZ, Dvorak or another input method.
That distinction matters when troubleshooting. If KeyQ lights up but the key value is a, the physical key is being delivered and the difference is probably the active layout. If no event appears for a key that should be available to the page, the issue may be hardware, firmware, the operating-system driver, the browser or a shortcut reserved before the web page can see it.
| Diagnostic | What it means | Useful for |
|---|---|---|
| Physical code | Hardware-position code like KeyA or Numpad5 |
Checking the physical switch that fired |
| Key value | Character or action produced by the active layout | Spotting layout or modifier differences |
| Location | Standard, left, right or numpad | Testing Shift, Ctrl, Alt and numpad variants |
| Rollover peak | Highest number of keys held at once during the session | Quick check for combo limits or ghosting |
| Repeat events | Browser repeat events while a key is held | Finding keys that repeat unexpectedly |
| Stuck-key warning | A held key older than your selected threshold | Catching keys that did not release cleanly |
Rollover, ghosting and limits
Keyboard rollover is the number of simultaneous key presses a keyboard can report. Many office keyboards handle common two-key or three-key combinations, while gaming keyboards may advertise 6-key rollover or N-key rollover. This tester can show the key events that reach the browser, but it cannot prove keys that the keyboard, OS or browser never delivered. Treat the rollover peak as a practical web-page check, not a laboratory hardware certificate.
Common pitfalls
- Keep the tab focused. Switching tabs or opening the address bar can interrupt keyup events, so the tester clears held keys when the page loses focus.
- Some shortcuts are reserved by the browser or operating system, including combinations such as Alt+Tab, Cmd+Tab, Cmd+W, Cmd+L and F5.
- Mobile keyboards, virtual keyboards, IME composition, dead keys and accessibility tools can change or delay the reported key value.
- If one key fails here, test another browser and another USB port before assuming the switch itself is broken.
Frequently Asked Questions
No. Key events are read and displayed in your browser. The tool does not upload key values, physical codes, timing data or event history to a server.
Browsers and operating systems reserve some keys and shortcuts before a page can read them. System combinations such as Alt+Tab, Cmd+Tab, Cmd+L or browser refresh may never be delivered to this tester.
event.code is the physical key position, while event.key is the character or action produced by your active keyboard layout. A layout change can alter the key value without changing the physical code.
It can show the highest number of keys that reached the browser at once during your test. It cannot certify keys that the keyboard firmware, operating system or browser filters before the page receives them.
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