JS操作select下拉框动态变动(创建/删除/获取)

1.动态创建select 

function createSelect(){ 
var mySelect = document.createElement_x("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.getElementByIdx_x('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.getElementByIdx_x('mySelect'); 
obj.options.length=0; 
} 

4.删除一个选项option 

function removeOne(){ 
var obj=document.getElementByIdx_x('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.getElementByIdx_x('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.getElementByIdx_x('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.getElementByIdx_x('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.getElementByIdx_x("mySelect"); 
mySelect.parentNode.removeChild(mySelect); 
}