Key Event Tester

A keyboard event is a browser object created whenever a user interacts with a physical or virtual keyboard. The primary events are keydown (when a key is depressed) and keyup (when a key is released).

keydown fires the moment a key is pressed down, before character input is committed. If held down, operating systems usually emit repeated keydown events. keyup fires once when the physical key rebounds and is released.

event.key represents the character value or semantic action generated by the key according to your current OS keyboard language and active modifier keys (e.g. 'a', 'A', 'Enter', 'Shift').

event.code represents the physical position of the key on the keyboard, independent of the operating system language layout (e.g. 'KeyQ', 'Digit1', 'Space', 'ShiftLeft').

event.location identifies which physical cluster the key belongs to: 0 (Standard), 1 (Left modifier), 2 (Right modifier), or 3 (Numpad).

event.repeat is a boolean flag that is true when a keydown event is fired repeatedly due to the user holding the key down, driven by the operating system's repeat delay and rate settings.

Certain operating system shortcuts (like Alt+Tab, Windows Key, or Ctrl+Alt+Del) or browser shortcuts (like Ctrl+N or Ctrl+W) are intercepted at a higher system level and never passed to the browser window.

In Capture Mode, the tool calls event.preventDefault() for supported keys (such as Space, Tab, and Arrows) to stop them from scrolling the page, but OS-level hotkeys remain reserved.

Yes. All modifier keys are tracked in real time. The Modifiers Panel and Selected Event Inspector display the boolean flags (ctrlKey, shiftKey, altKey, metaKey).

Yes. The Shortcut Inspector detects multi-key chords (like Ctrl + Shift + K) as they are held down, and signals 'COMBINATION COMPLETE' once released.

No. This tool measures Browser Event Timing—the timestamp when the JavaScript engine processes the event. It cannot directly measure physical switch debounce or USB polling rates.

No. All event inspection, log filtering, and statistics run strictly in client-side JavaScript. No keyboard events are ever uploaded or transmitted to any server.

Yes. It works across Windows, macOS, Linux, ChromeOS, iOS, and Android browsers, accurately identifying OS-specific modifier flags like Command/Meta.