.no { background:url(../images/biao_01.gif) no-repeat 10px 2px; float:left; cursor:pointer; width:30px; height:20px; position:absolute; display:block;}/*点击前的span*/
.yes { background:url(../images/biao_02.gif) no-repeat 10px 3px; float:left; cursor:pointer; width:30px; height:20px; position:absolute;display:block;}/*点击后的span*/