var i = 3;
var timerID = 0;
var nextY;
var markY = 10000;
var bnavi = window.navigator.userAgent;

function CurtY(){
	if(document.all){
		if( bnavi.lastIndexOf('MSIE 7.0') != -1 ){
			return document.documentElement.scrollTop;
		} else {
			return document.body.scrollTop;
		}
	} else if(document.layers || document.getElementById){
		return window.pageYOffset;
	}
}


function Scroll(){
	nextY = CurtY();
	nextY += (0 - nextY)/i;

	if (CurtY() <= markY){
		clearTimeout(timerID);
		window.scrollTo(0,nextY);
		markY = CurtY();
	} else {
		nextY = 0;
	}

	if (nextY != 0){
		timerID = setTimeout("Scroll();",30);
	} else{ 
		markY = 10000;
	}
}