Keyboard Tester

Press any key to see its name, keyCode, code and modifier state

What is it and how does it work?

A keyboard tester lets you verify that every key on your keyboard registers correctly in the browser. When you press a key, the tool highlights it on an on-screen keyboard layout and shows the key code, key name, and any modifier states (Shift, Ctrl, Alt, Meta). This is essential for diagnosing sticky keys, unregistered keypresses, or inconsistent behaviour after cleaning, water damage, or firmware updates.

Keyboard testers are also useful for developers and gamers. Developers use them to understand JavaScript KeyboardEvent properties — `key`, `code`, `keyCode`, `which`, and modifier flags — to write correct event handlers. Gamers use them to test n-key rollover (NKRO) and anti-ghosting: whether multiple simultaneous keypresses all register correctly, which matters for fast-paced gameplay.

Common use cases

• Dead key diagnosis: press each key in a region of your keyboard (e.g., the number row or left side) to confirm every physical key fires a JavaScript event — spotting the dead key without disassembly.
• N-key rollover test: hold down WASD or arrow keys simultaneously and add other keys to confirm all keypresses register concurrently (important for gaming peripherals).
• Developer reference: check the exact `code` value (e.g., "KeyA", "Numpad0", "F12") your browser reports for a physical key to write platform-correct event handler code.

Frequently asked questions

What is the difference between `key` and `code` in a keyboard event?

`key` is the logical key value — "A" for the A key, "Shift" for the shift key, "Enter" for enter. It changes with modifier keys: Shift+A gives "A". `code` is the physical key location — "KeyA", "ShiftLeft", "Enter" — regardless of what character it produces. For layout-independent shortcuts (WASD gaming), use `code`. For text input, use `key`.

Why doesn't the keyboard tester capture some key combinations?

Operating systems and browsers intercept certain combinations before JavaScript sees them. Ctrl+W closes the browser tab; Alt+F4 closes the window; Ctrl+Alt+Del is reserved by the OS. These keys cannot be captured in a browser-based tester.

What is keyboard ghosting?

Ghosting occurs when a keyboard fails to report a keypress because too many other keys are held down simultaneously. Budget keyboards typically support 3–6 keys at once; mechanical and gaming keyboards advertise NKRO (n-key rollover), meaning any number of simultaneous keypresses all register correctly.

Can I test a wireless or Bluetooth keyboard?

Yes. The keyboard tester works at the browser level, receiving KeyboardEvent objects from whatever input device the OS forwards. It doesn't matter if the keyboard is wired, wireless, or Bluetooth — as long as the OS sees the keypress and routes it to the browser, the tester will catch it.

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