Key Press Listener for JavaScript

key-press-listener.js

'use strict';

(function(window){

    /**
     * Function: Keydown
     *
     * Manipulate keypress actions.
     *
     * Parameters:
     *     (Object) evt - Keydown object
     *
     * Returns:
     *     null
     */
    function Keydown(evt) {
        switch (evt.keyCode) { // keyCode source: http://www.asquare.net/javascript/tests/KeyCode.html
            case 38: // Up
            case 37: // Left
            case 39: // Right
            case 40: // Down
                break;
        }
    }
    window.onkeydown = Keydown;

})(window);