function scrollTop(){
	if(isNaN(window.pageYOffset)){
		scrollNum = document.body.scrollTop;
		if(isNaN(scrollNum)){
			scrollNum = 800;
		}
	}else{
		scrollNum = window.pageYOffset;
		if(isNaN(scrollNum)){
			scrollNum = 800;
		}
	}
	scrollNum2 = (scrollNum > 100) ? Math.floor(scrollNum/2) : Math.floor(scrollNum/3);
	var TimeID;
	if(scrollNum < 3){
		scrollTo(0,0);
		clearTimeout(TimeID);
	}else{
		scrollBy(0,-scrollNum2);
		TimeID = setTimeout("scrollTop()",20);
	}
}