defaultStep = 5;
step = defaultStep;

function scrollDivDown(id) { 
    clearTimeout(timerDown);
    document.getElementById(id).scrollTop += step;
    timerDown = setTimeout("scrollDivDown('" + id + "')", 10);
}  

function scrollDivUp(id) { 
    clearTimeout(timerUp);
    document.getElementById(id).scrollTop -= step;
    timerUp = setTimeout("scrollDivUp('" + id + "')", 10);
}  

timerDown = "";
timerUp = "";

function stopMe() {
    clearTimeout(timerDown);
    clearTimeout(timerUp);
} 

document.onmousemove = function() { stopMe(); }