Konami code

konami.js

var input = "";
var konamiLetters = "72726666716871686665";
            var konamiArrow = "38384040373937396665";

            document.onkeydown = function(evt){
                evt = evt || window.event;
                input +=  evt.keyCode;
            };

            var timer = setInterval(function(){
                if(input !== null || input !== undefined){
                    if(input === konamiLetters || input === konamiArrow){

                        console.log('You win ! :) Well done for trying ;)');

                        clearInterval(timer);


                        return true;
                    }
                }
            }, 500);