var currentpos,timer; 

function initialize() 
{ 
 timer=setInterval("scrollwindow()",30);
} 

function sc()
{
 clearInterval(timer);	
}

function scrollwindow() 
{ 
 currentpos=document.body.scrollTop; 
 window.scroll(0,++currentpos); 
 if (currentpos != document.body.scrollTop) 
  sc();
} 
document.onmousedown=sc
document.ondblclick=initialize