Keyboard tester
Press any key and it lights up on the on-screen keyboard. Keys you have already pressed stay tinted, so you can walk across the keyboard and spot a key that does not respond. Nothing is stored.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Click an empty part of the page so it receives keys, and press a key.
- The key lights up dark while held and stays tinted afterwards. Work your way along every row.
- The panel shows the key name, its physical code and whether it is the left, right or numpad version.
- Clear resets the tint and the list.
How it works
The page listens for key down and key up events. The cell on the layout is chosen by event.code, which identifies the physical key independent of the language layout, so a Russian or French keyboard lights the same places as a US one.
Key rollover is limited by the hardware: if a cheap keyboard cannot report many keys at once, holding several keys will make some of them stop lighting. That is a keyboard limit, not the page’s.
Worked example
Press the left Shift key and then A. The panel shows Key Shift, Code ShiftLeft, Location Left, and the left Shift cell is dark. Then it shows Key A, Code KeyA, Location Standard. Press the right Shift and the code becomes ShiftRight, which shows that the two keys are told apart.
Tips
- Ghosting. Some keyboards drop a key when several others are held. Test combinations you use in games.
- Stuck keys. A key that stays dark after release is stuck, or the window lost focus; click the page and press it again.
Frequently asked questions
What is the difference between key and code?
Key is the character or function the press produces, such as "a" or "Enter", and depends on your layout and Shift. Code names the physical key, such as KeyA, wherever it sits. The layout above is lit by code, so it works with any layout.
A key does not light up. Is it broken?
It may be. Press it several times first, then try it in another program. Some laptop keys, such as Fn, are handled by the hardware and never reach the browser, and the system can intercept a few shortcuts.
Why do some keys do nothing to the page?
While the page is open, keys such as Space, Tab and the arrows are kept from scrolling or moving focus, so you can test them. Shortcuts with Ctrl, Alt or the Windows or Command key still go to the browser.
Does the tester record what I type?
No. It only keeps the last dozen presses on the page for display and forgets them when you clear or leave. Nothing is sent anywhere.
Why is there no numpad on the layout?
The picture shows the main block and the arrow keys. Numpad keys still work and appear in the Key, Code and Location fields, with the location set to Numpad.