Keyboard API

On physical keyboards, the code attribute contains the physical location of the key that was pressed, and the key attribute contains the string generated by pressing the key at that physical location on the keyboard. The key value takes into account the keyboard's locale (for example, 'en-US'), layout (for example, 'QWERTY'), and modifier-key state (Shift, Control, etc.). Historically there has been no way to retrieve that information.

The Keyboard Map API provides a way to retrieve the string generated by a particular key press, through the Keyboard interface and the KeyboardLayoutMap interface. The Keyboard interface is accessed through navigator.keyboard. Keyboard provides the Keyboard.getLayoutMap method, which returns a promise that resolves with a KeyboardLayoutMap object that contains members for converting codes to keys. A list of valid code values is found in the Writing System Keys section of the UI Events KeyboardEvent code Values spec.

The following example demonstrates how to get the location-specific or layout-specific string associated with the key labeled W on an English QWERTY keyboard.

if (navigator.keyboard) {
  const keyboard = navigator.keyboard;
  keyboard.getLayoutMap().then((keyboardLayoutMap) => {
    const upKey = keyboardLayoutMap.get("KeyW");
    window.alert(`Press ${upKey} to move up.`);
  });
} else {
  // Do something else.
}

Richly interactive web pages, games, and remote-streaming experiences often require access to special keys and keyboard shortcuts while in fullscreen mode. Examples of such key/key combinations include Escape, Alt+Tab, and Ctrl+N. Those keys and key combinations are typically captured by the user agent or the underlying operating system, as illustrated in the following example.

To capture the W, A, S, and D keys, call lock() with a list that contains the key code attribute value for each of these keys:

navigator.keyboard.lock(["KeyW", "KeyA", "KeyS", "KeyD"]);

This captures these keys regardless of which modifiers are used with the key press. Assuming a standard United States QWERTY layout, registering KeyW ensures that W, Shift+W, Control+W, Control+Shift+W, and all other key modifier combinations with W are sent to the app. The same applies to for KeyA, KeyS, and KeyD.

The codes passed Keyboard.lock and the various methods of the KeyboardLayoutMap interface are called "writing system keys".

"Writing system keys" are defined in the Writing System Keys section of the UI Events KeyboardEvent code Values spec, since the physical keys change meaning based on the current locale and keyboard layout. These keys are shown below. Blue keys are present on all standard keyboards while green keys are only available on some keyboards.

Keyboard Experimental

Provides functions that retrieve keyboard layout maps and toggle capturing of key presses from the physical keyboard.

KeyboardLayoutMap Experimental

A map-like object with functions for retrieving the string associated with specific physical keys.

navigator.keyboard Read only Experimental

Returns a Keyboard object which provides access to functions that retrieve keyboard layout maps and toggle capturing of key presses from the physical keyboard.