var goto_top_type = -1;
var goto_top_itv = 0;

function goto_top_timer() {
var y = goto_top_type == 1 ? document.documentElement.scrollTop : document.body.scrollTop; //alert(y);
var moveby = 15; //  scroll speed

y -= Math.ceil(y * moveby / 100);
if (y < 0)
y = 0;

if (goto_top_type == 1)
	document.documentElement.scrollTop = y;
else
	document.body.scrollTop = y;

if (y == 0) {
	clearInterval(goto_top_itv);
	goto_top_itv = 0;
	}
}

function goto_top() {
	if (goto_top_itv == 0) {
		if (document.documentElement && document.documentElement.scrollTop)
			goto_top_type = 1;
		else if (document.body && document.body.scrollTop)
			goto_top_type = 2;
		else
			goto_top_type = 0;

		if (goto_top_type > 0)
			goto_top_itv = setInterval('goto_top_timer()', 25);
	}
}