Select 相关知识总结

         

平时很少用select，顺便把相关的知识总结一下
1.动态创建select

   function createSelect(){

       var mySelect = document.createElement("select");
       mySelect.id = "mySelect"; 
       document.body.appendChild(mySelect);
   }

2.添加选项option

  function addOption(){

       //根据id查找对象，
        var obj=document.getElementById('mySelect');

        //添加一个选项
        obj.add(new   Option("文本","值"));  
  }

3.删除所有选项option

  function removeAll(){
        var obj=document.getElementById('mySelect');
 
        obj.options.length=0; 

  }

4.删除一个选项option

function removeOne(){
        var obj=document.getElementById('mySelect');

        //index,要删除选项的序号，这里取当前选中选项的序号

        var index=obj.selectedIndex;
        obj.options.remove(index); 
  }

5.获得选项option的值

var obj=document.getElementById('mySelect');

var index=obj.selectedIndex; //序号，取当前选中选项的序号

var val = obj.options[index].value;

6.获得选项option的文本

var obj=document.getElementById('mySelect');

var index=obj.selectedIndex; //序号，取当前选中选项的序号

var val = obj.options[index].text;

7.修改选项option

var obj=document.getElementById('mySelect');

var index=obj.selectedIndex; //序号，取当前选中选项的序号

var val = obj.options[index]=new Option("新文本","新值");

8.删除select

   function removeSelect(){
         var mySelect = document.getElementById("mySelect");
        mySelect.parentNode.removeChild(mySelect);
  }