defaultStep=3  
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()}