Better ways of making a scroller

Question

http://jsfiddle.net/xkuZF/6/

function func() {
    document.body.scrollTop++;
}

window.onmouseover = function() {
    clearInterval(interval);
};

window.onmouseout = function() {
    interval = setInterval(func);
};

var interval =  setInterval(func);

Do you think that there are any better ways of doing this code?

Better:

• More options
• Less code