'use strict'; var Key = { LEFT: "ArrowLeft", UP: "ArrowUp", RIGHT: "ArrowRight", DOWN: "ArrowDown" }; function handleKeyboardEvent(event) { var info = document.getElementById("info"); switch (event.key) { case Key.LEFT: info.value += "LEFT "; break; case Key.UP: info.value += "UP "; break; case Key.RIGHT: info.value += "RIGHT "; break; case Key.DOWN: info.value += "DOWN "; break; default: info.value += "SOMEKEY "; } } document.addEventListener("keydown", handleKeyboardEvent);