var defaultStep=1;
var 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)
} 

var timerDown="";
var timerUp="";

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

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