推荐订阅源

1 检测是否有选中
if(objSelect.selectedIndex > -1) {
//说明选中
} else {
//说明没有选中
}

2.动态创建 select

function createSelect(){

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

3.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"));
}

4.删除所有选项 option

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

obj.options.length=0;

}

5.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);
}

6.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;

7.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;

8.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");

9.删除 select

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