select下拉框右對齊，去掉箭頭，替換箭頭

右對齊

select{
   width:auto;
   direction: rtl;
}
select option { 
　　direction: ltr; 
}

去掉箭頭（不設置背景色會有灰色背景）

select{
   appearance:none;
   -moz-appearance:none;
   -webkit-appearance:none;
   background-color: #fff;
   /*設置箭頭*/
   background: url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAwAAAAJCAYAAAAGuM1UAAAAH0lEQVR42mNgoDnQ13f7TwiTpIkkm0hyHkl+YhhQAABcfyjsqSyTLgAAAABJRU5ErkJggg==") no-repeat scroll right center transparent;
   padding-right: 14px;
}

清除ie的默認選擇框樣式，隱藏下拉箭頭

select::-ms-expand { 
   display: none;
}