How to use it
- Click the keyboard picture to capture keys. While it is active, keys such as Tab, F5 and the arrows are used by the test instead of the browser.
- Press every key and watch it turn green. The counter at the top shows how many you have confirmed.
- If a key stays unlit, press it a few more times, then try another USB port or computer.
Some shortcuts the browser keeps for itself, such as Ctrl+W, and the Fn key on laptops never reach a web page, so they cannot be tested. Keys that only send a signal on release, like Print Screen on Windows, are confirmed when you let go.
Rollover and ghosting
Rollover is how many keys can be held at once and still register; a keyboard that handles all of them is called N-key rollover (NKRO). Ghosting is when certain combinations add a key you did not press or drop one you did.
Hold a combination you use in games, such as W, A, Shift and Space, and check the Max at once counter and the on-screen keys. Every key you hold should be lit blue. Some USB keyboards are limited to 6-key rollover depending on the mode they run in.
key versus code
In the details panel, code is the physical position of the key (for example KeyA) and key is the value it produces with your current layout and Shift state (for example a or A). While an input method editor is active, key may show as Process. Keys outside the drawn layout, such as language or media keys, are listed separately.