var op=document.createElement("option");
op.text=clos[i];
op.value=clos[i];
//sel.options.add(new Option(clos[i],clos[i]));
sel.options.add(op);
}
----------------------------------------------------------------
Option里面的四个参数分别的意思
new Option (text,value,defaultselected,selected)
new Option (文本,值,默认选中的选项,选中的选项)
看测试结果就懂了
<select id="s1"></select>
<script>
var op = new Option("显示文本1","值1",false,false);
s1.options.add(op);
op = new Option("显示文本2","值2",false,true);
s1.options.add(op);
</script>
-----------------------------------------------------------------
3.删除所有选项option
Javascript代码
function removeAll(){
var obj=document.getElementById('mySelect');
obj.options.length=0;
}
4.删除一个选项option
Javascript代码
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
Javascript代码
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
Javascript代码
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
Javascript代码
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
Javascript代码
function removeSelect(){
var mySelect = document.getElementById("mySelect");
mySelect.parentNode.removeChild(mySelect);
}
整个实例的完整代码如下:
Javascript代码
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//ZH-CN" "
http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html">
<head>
<script language=JavaScript>
function $(id)
{
return document.getElementById(id)
}
function show()
{
var selectObj=$("area")
var myOption=document.createElement("option")
myOption.setAttribute("value","10")
myOption.appendChild(document.createTextNode("上海"))
var myOption1=document.createElement("option")
myOption1.setAttribute("value","100")
myOption1.appendChild(document.createTextNode("南京"))
selectObj.appendChild(myOption)
selectObj.appendChild(myOption1)
}
function choice()
{
var index=$("area").selectedIndex;
var val=$("area").options[index].getAttribute("value")
if(val==10)
{
var i=$("context").childNodes.length-1;
var remobj=$("context").childNodes[i];
remobj.removeNode(true)
var sh=document.createElement("select")
sh.add(new Option("浦东新区","101"))
sh.add(new Option("黄浦区","102"))
sh.add(new Option("徐汇区","103"))
sh.add(new Option("普陀区","104"))
$("context").appendChild(sh)
}
if(val==100)
{
var i=$("context").childNodes.length-1;
var remobj=$("context").childNodes[i];
remobj.removeNode(true)
var nj=document.createElement("select")
nj.add(new Option("玄武区","201"))
nj.add(new Option("白下区","202"))
nj.add(new Option("下关区","203"))
nj.add(new Option("栖霞区","204"))
$("context").appendChild(nj)
}
}
function calc()
{
var x=$("context").childNodes.length-1;
alert(x)
}
function remove()
{
var i=$("context").childNodes.length-1;
var remobj=$("context").childNodes[i];
remobj.removeNode(true)
}
</script>
<body>
<div id="context">
<select id="area" onchange="choice()">
</select>
</div>
<input type=button value="显示" onclick="show()">
<input type=button value="计算结点" onclick="calc()">
<input type=button value="删除" onclick="remove()">
</body>
</html>
改进版:在select中添加、修改、删除option元素
Javascript代码
function watch_ini(){ // 初始
for(var i=0; i<arguments.length; i++){
var word = document.createElement("OPTION");
word.text = arguments[i];
watch.keywords.add(word); // watch. is form name
}
}
function watch_add(f){ // 增加
var word = document.createElement("OPTION");
word.text = f.word.value;
f.keywords.add(word);
}
但上述 add() 方法只在IE下有效,为兼容FF和Opera,对上述代码进行了一下改进,改动后代码如下: function watch_ini(){ // 初始
Javascript代码
for(var i=0; i<arguments.length; i++){
var oOption=new Option(arguments[i],arguments[i]);
document.getElementById("MySelect")[i]=oOption;
}
}
function watch_add(f){ // 增加
var oOption=new Option(f.word.value,f.word.value);
f.keywords[f.keywords.length]=oOption;
}