var speed = 30;
var tab = document.getElementById("demo");
var tab1 = document.getElementById("demo1");
var tab2 = document.getElementById("demo2");
tab2.innerHTML = tab1.innerHTML;
function Marquee() {
    if (tab2.offsetWidth - tab.scrollLeft <= 0)
        tab.scrollLeft -= tab1.offsetWidth
    else {
        tab.scrollLeft++;
    }
}
var MyMar = setInterval(Marquee, speed);
tab.onmouseover = function() { clearInterval(MyMar) };
tab.onmouseout = function() { MyMar = setInterval(Marquee, speed) };