konami.js

(function() {
	var codes = [];
	var codeCount = 0;
	window.addEventListener('keyup', function(e) {
		if (codes.length == 10) codes.shift();
		codes.push(e.keyCode);
		if (codes.join(",") == "38,38,40,40,37,39,37,39,66,65") {
			codeCount++;
			var event = new CustomEvent('konami');
			event.konamiCount = codeCount;
			document.dispatchEvent(event);
		}
	});
})();