defaultStep=1 
step=defaultStep 

function scrollDivDown(id){
clearTimeout(timerDown) 
document.getElementById(id).scrollTop+=step 
timerDown=setTimeout("scrollDivDown('"+id+"')", 1)

} 

function scrollDivUp(id){
clearTimeout(timerUp)
document.getElementById(id).scrollTop-=step 
timerUp=setTimeout("scrollDivUp('"+id+"')", 1)
} 

timerDown="" 
timerUp="" 

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

document.onmouseout=function(){stopMe()}