#roll_top, #fall, #ct{position: relative;cursor: pointer;height: 72px;width: 26px;}
#roll_top{background: url(../images/top.gif) no-repeat;}
#fall{background: url(../images/top.gif) no-repeat 0 -80px;}
#ct{background: url(../images/top.gif) no-repeat 0 -40px;}
#roll{display: block;width: 15px;margin-right: -500px;position: fixed;right: 50%;top: 50%;_margin-right: -505px;
_position: absolute;_margin-top: 300px;_top: expression(eval(document.documentElement.scrollTop));}