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);
}