1. KeyboardEvent.getModifierState()

    `KeyboardEvent` method that returns the state (whether the key is pressed/locked or not) of the given modifier key.

  2. element api: requestfullscreen: `options` parameter: `keyboardlock` option

  3. keyboardevent api: getmodifierstate: `"capslock"` as `key` parameter

  4. keyboardevent api: getmodifierstate: `"numlock"` as `key` parameter

  5. keyboardevent api: getmodifierstate: `"scrolllock"` as `key` parameter

  6. keyboard api: lock

  7. keyboard api: unlock