Konami Kode in JS.

konami.js

/**
 * konami.js - copyright (c) 2014-2016 rummik
 * license: Public Domain / CC0 / WTFPL
 * source: https://gist.github.com/rummik/10633824
 * usage:
 *   window.addEventListener('konami', function() { ... })
 *   window.onkonami = function() { ... }
 */

(function() {
	var kode = [38, 38, 40, 40, 37, 39, 37, 39, 66, 65];
	var stak = new Array(kode.length);

	window.addEventListener('keydown', function konami(event) {
		stak.shift();
		stak.push(event.keyCode);

		if (stak.toString() == kode) {
			window.dispatchEvent(new CustomEvent('konami'));

			if (typeof window.onkonami == 'function') {
				window.onkonami();
			}
		}
	});
})();