var timer;
function rollstart(){
	timer=setInterval("scrollwindow()",40);
	document.onclick=sc;
}
function sc(){
	clearInterval(timer);
	document.ondblclick=rollstart;
}
function scrollwindow() {
	currentpos=document.body.scrollTop;
	window.scroll(0,++currentpos);
	if (currentpos != document.body.scrollTop){
		sc();
	}
}
document.ondblclick=rollstart;