1 檢測(cè)是否有選中
if(objSelect.selectedIndex > -1) {
//說明選中
} else {
//說明沒有選中
}

2.動(dòng)態(tài)創(chuàng)建select

function createSelect(){

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

3.添加選項(xiàng)option

function addOption(){

//根據(jù)id查找對(duì)象，
var obj=document.getElementById('mySelect');

//添加一個(gè)選項(xiàng)
obj.add(new Option("文本","值"));
}

4.刪除所有選項(xiàng)option

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

obj.options.length=0;

}

5.刪除一個(gè)選項(xiàng)option

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

//index,要?jiǎng)h除選項(xiàng)的序號(hào)，這里取當(dāng)前選中選項(xiàng)的序號(hào)

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

6.獲得選項(xiàng)option的值

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

var index=obj.selectedIndex; //序號(hào)，取當(dāng)前選中選項(xiàng)的序號(hào)

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

7.獲得選項(xiàng)option的文本

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

var index=obj.selectedIndex; //序號(hào)，取當(dāng)前選中選項(xiàng)的序號(hào)

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

8.修改選項(xiàng)option

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

var index=obj.selectedIndex; //序號(hào)，取當(dāng)前選中選項(xiàng)的序號(hào)

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

9.刪除select

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