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;
	var moveby = 15;

	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()', 50);
	}
}