Keyboard Tester

Check browser-visible key events

Click or tap the bordered keyboard, then press and release keys. The visual layout highlights pressed keys and reports the browser's key value, physical-position code, modifiers, repeat state, and simultaneous pressed set. When the complete keyboard cannot fit, it automatically stacks the function, main, navigation, and number-pad sections without sideways scrolling.

Key versus code

event.key describes the interpreted value, such as a lowercase letter or Enter. event.code describes a physical keyboard position, such as KeyA, independent of the active character layout. That difference matters when diagnosing shortcuts, games, alternate layouts, and remapped keyboards.

Worked example

Focus the tester and hold the left Shift key while pressing A. The page should show A as the key, KeyA as the code, Shift as a modifier, and both positions in the pressed list until released. Holding a letter may produce repeat keydown events after the operating system's repeat delay.

Testing rollover and stuck keys

Hold several ordinary keys together and watch the pressed list. Missing combinations can result from hardware rollover limits, keyboard firmware, wireless behavior, operating-system shortcuts, or browser interception. A highlight that disappears on release suggests the page received both events. If focus leaves the tester, pressed state is cleared to avoid falsely displaying stuck keys.

Browser and operating-system boundaries

Some combinations never reach a web page because the browser or operating system reserves them. Function keys, media controls, special vendor keys, Fn layers, secure-attention combinations, and input-method behavior vary by device. The visual layout is a compact common keyboard, not a promise that every regional or extended key has a matching box.

Privacy and limitations

Events are handled only while the test area has focus and are not stored or transmitted. This page cannot inspect keyboard firmware, scan rate, electrical switches, latency, debounce quality, Bluetooth signal, macros, or another application. It is diagnostic evidence, not hardware certification.

Keyboard Tester FAQ

Why does a key perform a browser action?

The tester blocks many default actions while focused, but protected operating-system shortcuts remain outside page control.

Can this measure input latency?

No. It confirms delivered events but lacks external timing hardware and a physical actuation reference.

Does it record what I type?

No. The latest event appears on screen and disappears when the page closes.