function toTop(id){ 
document.getElementById(id).scrollTop=0 
} 

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) 
} 

function toBottom(id){ 
document.getElementById(id).scrollTop=document.getElementById(id).scrollHeight 
} 

function toPoint(id){ 
document.getElementById(id).scrollTop=100 
} 

window.onload = function controlScrollVisible(){
    if(document.getElementById("content").scrollHeight<270){
       document.getElementById("scroll").style.display = "none";
    }
}