下拉框隐藏样式，只保留内容

<style type="text/css">

select{
    auto;
    direction: rtl;
    float: right;
}
select option {
    　　direction: ltr;
}
select{
    border: 0;
    appearance:none;
    -moz-appearance:none;
    -webkit-appearance:none;
    /**/
    /*设置箭头*/
    /*background: url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAwAAAAJCAYAAAAGuM1UAAAAH0lEQVR42mNgoDnQ13f7TwiTpIkkm0hyHkl+YhhQAABcfyjsqSyTLgAAAABJRU5ErkJggg==") no-repeat scroll right center transparent;*/
   /* padding-right: 14px;*/
}
/*select::-ms-expand {
    display: none;
}*/
</style>