javascript tap and hold

var onlongtouch; 
var timer;
var touchduration = 800; //length of time we want the user to touch before we do something

function touchstart(e) {
    e.preventDefault();
    if (!timer) {
        timer = setTimeout(onlongtouch, touchduration);
    }
}

function touchend() {
    //stops short touches from firing the event
    if (timer) {
        clearTimeout(timer);
        timer = null;
    }
}

onlongtouch = function() { 
    timer = null;
    document.getElementById('ping').innerText+='ping\n'; 
};

document.addEventListener("DOMContentLoaded", function(event) { 
    window.addEventListener("touchstart", touchstart, false);
    window.addEventListener("touchend", touchend, false);
});