progressive konami code

Question

I am trying to create a .js file for a website that upon entering the konami code Up, Up, Down, Down, Left, Right, Left, Right, B, A, Start(enter) it will embed a video. However while entering the right keys the webpage should display something like "keep going", if a wrong key is entered it should display "wrong, try again", and allow them to start over.

I've manged to get the JavaScript working where upon entering the right code it displays an alert, and entering the wrong code displays a different code.

i've manged to get this much code using online resources but none of them explain how to get wrong, try again part

    if (window.addEventListener) {
    var keys = [],
    konami = "38,38,40,40,37,39,37,39,66,65,13";

    window.addEventListener("keydown", function(e){
    keys.push(e.keyCode);


    if (keys.toString().indexOf(konami) >= 0) 
    {            
       alert('Right');
        keys = [];
    };

    if (keys.toString().indexOf(konami) < 0)
    {
       alert('Wrong');
        keys = [];
    }
}, true);

};

Any help would be greatly appreciated.

Answer 1

if (window.addEventListener) {
    var index = 0;
    var konami = [38,38,40,40,37,39,37,39,66,65,13];

    window.addEventListener("keydown", function(e){
        if (e.keyCode === konami[index])
        {
            index++; //valid key at the valid point

            if (index == konami.length)
            {
                alert("Correct");
            } else {
                alert("Keep going");
            }
        } else {
            // incorrect code restart
            index = 0;
            alert("Wrong"); 
        }
   });
}

Answer 2

You could do something like

 if (window.addEventListener) {
    var keys = [],
    konami = "38,38,40,40,37,39,37,39,66,65,13".split(',');

    window.addEventListener("keydown", function(e){
    keys.push(e.keyCode);
        console.log(e.keyCode);
    var lengthOfKeys = keys.length -1;


    if (konami[lengthOfKeys] == keys[lengthOfKeys])
    {            
       alert('Right');
        if(konami.length === keys.length){
            alert('complete!');
        }

    }else{
       alert('Wrong');
        keys = [];
    }
}, true);
};

fiddle here http://jsfiddle.net/b6kuZ/