#floating_box{
	position: fixed;
	bottom: 40px;
	width: 50px;
	height: 50px;
	display: none;
}
#floating_box .goTopBtn{
	display: block;
	width: 50px;
	height: 50px;
	background-image: url("http://img.china.alibaba.com/cms/upload/2012/767/193/391767_286271235.png");
	background-position: 0 0;
}
#floating_box .goTopBtn:hover{
	background-position: 0 -80px;
}