.mainbox{
    overflow:hidden;
    position:relative;
}
.flashbox{
   overflow:hidden;
    position:relative;
}
.imagebox{
    text-align:center;position:relative;z-index:999;
}

.bitdiv{display:inline-block;width:12px;height:12px;margin:0 10px 10px 0px;cursor:pointer}
.defimg{background:url(btn.jpg) no-repeat left bottom;}
.curimg{background:url(btn.jpg) no-repeat left top;}