defaultStep=5
step=defaultStep  

yCord = 0

function scrolliframeDown(id){
clearTimeout(timerDown)
yCord = yCord + step
document.getElementById(id).contentWindow.scrollTo(0, yCord)
timerDown=setTimeout("scrolliframeDown('"+id+"')",10)
}

function scrolliframeUp(id){
clearTimeout(timerUp)
yCord-=step
document.getElementById(id).contentWindow.scrollTo(0, yCord)
timerUp=setTimeout("scrolliframeUp('"+id+"')",10)
}

timerDown=""  
timerUp=""  

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

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