var scspeed = 3;
var sctimerID = 0;
var new_scY;

function go_top() {
	if(sctimerID) {
		clearInterval(sctimerID);
	}
	new_scY = 0;
	sctimerID = setInterval("anchor_top()",50);
}

function anchor_top() {
	if(new_scY && new_scY < getScrollTop() && sctimerID) {
		clearInterval(sctimerID);
	}
	var num = (getScrollTop() - 0);
	if(num > 1) {
		new_scY = getScrollTop() - num / scspeed;
		window.scrollTo(0,new_scY);
	} else {
		window.scrollTo(0,0);
		clearInterval(sctimerID);
	}
	
}

function getScrollTop(){
	if(( navigator.appName.indexOf( "Microsoft Internet Explorer", 0 ) != -1 )){
		if(document.documentElement.scrollTop) {
			return document.documentElement.scrollTop;
		} else {
			return document.body.scrollTop;
		}
	} else if(window.pageYOffset ){
		return window.pageYOffset;
	} else{
		return 0;
	}

}