JS动态添加option和删除option

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")); //这个只能在IE中有效
    obj.options.add(new Option("text","value")); //这个兼容IE与firefox
}

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);
}