#back-to-top{
    background: url('scroll.jpg') no-repeat;
    width: 50px;
    height: 49px;
    position:fixed;
    bottom:50px;
    right:20px;
   
    text-indent:-9999px;
	cursor:pointer;
}
#back-to-top:hover { filter:alpha(opacity=80);-moz-opacity:0.8;-khtml-opacity: 0.8;opacity: 0.8;}