.btn{float:right;margin:12px 10px;width:10px; height:10px;display:inline-block;background: url(../images/asdf.png) left center no-repeat;
 cursor:pointer;}
.btn1{float:right;margin:12px 10px;width:10px; height:10px;display:inline-block;background: url(../images/ddg.png) left center no-repeat;
 cursor:pointer;}

.on .btn{background: url(../images/ddg.png) left center no-repeat;
    display: block;} 
.erlm3 {
    display: none;}