(function(){

    var qselector = '#menu ul',

        time = 5000,

        item = document.querySelectorAll(qselector + ' > li'); // each li as menu item

        int = setInterval(next, time), i = 0, go = 1, 

        content = document.getElementById('content'),

        pause = document.querySelector(qselector + ' + .controls .pause');

​

    function show(num){

        i = (num + item.length) % item.length;

        content.src = item[i].getAttribute('data-src');

        }

    function stop(){

        go = 0; clearInterval(int);

        pause.innerHTML = 'Play';

        }

    function start(){ 

        go = 1; int = setInterval(next, time);

        pause.innerHTML = 'Pause'; 

        }

    function next(){ show(i+1); }

    function prev(){ show(i-1); }

    pause.addEventListener("click", function(){ go ? stop() : start(); });

    document.querySelector(qselector + ' + .controls .next').addEventListener("click", function(){ next(); stop(); });

    document.querySelector(qselector + ' + .controls .prev').addEventListener("click", function(){ prev(); stop(); });

​

    content.src = item[0].getAttribute('data-src'); // load 1st item

})();