defaultStep=1
step=defaultStep 
function scrollDivDown(id){ 
document.getElementById(id).scrollTop+=step 
timerDown=setTimeout("scrollDivDown('"+id+"')",10) 
} 

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