1.動(dòng)態(tài)創(chuàng)建select
   function createSelect(){
       var mySelect = document.createElement("select"); 
       mySelect.id = "mySelect";  
       document.body.appendChild(mySelect);
   }2.添加選項(xiàng)option
  function addOption(){
       //根據(jù)id查找對象，
        var obj=document.getElementById('mySelect');        //添加一個(gè)選項(xiàng)
        obj.options.add(new   Option("文本","值"));   
  }3.刪除所有選項(xiàng)option
  function removeAll(){
        var obj=document.getElementById('mySelect');
  
        obj.options.length=0;    }
4.刪除一個(gè)選項(xiàng)option
 function removeOne(){
        var obj=document.getElementById('mySelect');        //index,要?jiǎng)h除選項(xiàng)的序號，這里取當(dāng)前選中選項(xiàng)的序號
var index=obj.selectedIndex;
        obj.options.remove(index);  
  }5.獲得選項(xiàng)option的值
 var obj=document.getElementById('mySelect');
 var index=obj.selectedIndex; //序號，取當(dāng)前選中選項(xiàng)的序號
 var val = obj.options[index].value;
6.獲得選項(xiàng)option的文本
var obj=document.getElementById('mySelect');
 var index=obj.selectedIndex; //序號，取當(dāng)前選中選項(xiàng)的序號
 var val = obj.options[index].text;
7.修改選項(xiàng)option
var obj=document.getElementById('mySelect');
 var index=obj.selectedIndex; //序號，取當(dāng)前選中選項(xiàng)的序號
 var val = obj.options[index]=new Option("新文本","新值");
8.刪除select
   function removeSelect(){
         var mySelect = document.getElementById("mySelect");
        mySelect.parentNode.removeChild(mySelect);
  }9.選中其中的select
opt_uprice.options[i].selected=true;