js 操作select和option，添加select列
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);
???? }
9.设置selected
obj.options[1].selected=true
整个实例的完整代码如下：
<!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
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
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;
}
整个实例的完整代码如下：
<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
<html>
<head>
<title>javascript select options text value</title>
<meta name="keywords" content="javascript select options text value add modify delete set">
<meta name="description" content="javascript select options text value add modify delete set">
<script language="javascript">
<!--
function watch_ini(){ // 初始
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;
}
function watch_sel(f){ // 编辑
f.word.value = f.keywords[f.keywords.selectedIndex].text;
}
function watch_mod(f){ // 修改
f.keywords[f.keywords.selectedIndex].text = f.word.value;
}
function watch_del(f){ // 删除
f.keywords.remove(f.keywords.selectedIndex);
}
function watch_set(f){ // 保存
var set = "";
for(var i=0; i<f.keywords.length; i++){
set += f.keywords[i].text + ";";
}
confirm(set);
}
//-->
</script>
</head>
<body>
<form name="watch" method="post" action="">
<select id="MySelect" name="keywords" size="10" onchange="watch_sel(this.form)"></select><br>
<script language="javascript">
<!--
watch_ini("我","你","妳","他","她","它","尔"); // 初始关键词
//-->
</script>
<input type="text" name="word" /><br />
<input type="button" value="增加" onclick="watch_add(this.form);" />
<input type="button" value="修改" onclick="watch_mod(this.form);" />
<input type="button" value="删除" onclick="watch_del(this.form);" />
<input type="button" value="保存" onclick="watch_set(this.form);" />
</form>
用一个字符串创建一个数组方法:
<script language="javascript"> ??
