var currentpos, timer; 
var vera;
vera=true;
function initialize(){ 
if (vera==true) {timer = setInterval("scrollwindow1()", 1);}
if (vera==false){timer = setInterval("scrollwindow2()", 1);} 
} 
function sc(){ 
clearInterval(timer); 
} 
function scrollwindow1(){ 
currentpos = document.body.scrollTop; 
currentpos=currentpos+1;
window.scroll(0,currentpos);
if(currentpos != document.body.scrollTop){ vera=false;sc(); }
}
function scrollwindow2(){ 
currentpos = document.body.scrollTop; 
currentpos=currentpos-1;
window.scroll(0,currentpos)
if(currentpos != document.body.scrollTop){ vera=true;sc(); }  
} 
document.onmousedown = sc; 
document.ondblclick = initialize;