当我们注册一个网站，会看到省市区三级联动，下面简单介绍一下
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="Generator" content="EditPlus®">
<meta name="Author" content="">
<meta name="Keywords" content="">
<meta name="Description" content="">
<title>Document</title>
</head>
<body>
<select id="province" onChange="ck()" >
<option>--请选择--</option>
</select>
<select id="city">
<option>--请选择--</option>
</select>
<select id="san">
<option>--请选择--</option>
</select>
</body>
<script type="text/javascript">
//======================================第一种方法：获取省市二级联菜单=============================
//获取省的id
var prame= document.getElementById("province");
var city= document.getElementById("city");
var san= document.getElementById("san");
//创建省市数组
var cityList=new Array();
//创建另一个数组
var zushu=new Array;
cityList['江西省'] = ['南昌市','抚州市','上饶市','鹰潭市','丰城市','吉安市'];
cityList['河南省'] = ['郑州市','洛阳市'];
cityList['湖北省'] = ['武汉市','宜昌市'];
cityList['福建省'] = ['福州市','三明市','佛山市'];
zushu['南昌市']=['南昌县','青云谱区','莲塘镇'];
zushu['抚州市']=['临川区','云山镇','唱凯镇'];
for(var i in cityList){
prame.add(new Option(i,i),null);
}
prame.onchange=function(){
var prame= document.getElementById("province").value;
var city= document.getElementById("city");
city.options.length=0;
for(var k in cityList[prame]){
city.add(new Option(cityList[prame][k],cityList[prame][k]),null);
}
}
city.onchange=function(){
var city= document.getElementById("city").value;
var san= document.getElementById("san");
san.options.length=0;
for(var k in zushu[city]){
san.add(new Option(zushu[city][k]),(zushu[city][k]),null);
}
}
</script>
<!--------------------------------第二种方法：三级联动菜单----------------------
<script type="text/javascript">
//获取省的id
var province=document.getElementById("province");
province.add(new Option("江西省","江西省"),null);
province.add(new Option("福建省","福建省"),null);
province.add(new Option("广东省","广东省"),null);
function ck(){
var city=document.getElementById("city");
var num=province.selectedIndex;
city.options.length=0;
switch(num){
case 1:
city.add(new Option("南昌市","南昌市"),null);
city.add(new Option("抚州市","抚州市"),null);
city.add(new Option("上饶市","上饶市"),null);
city.add(new Option("吉安市","吉安市"),null);
break;
case 2:
city.add(new Option("厦门市","厦门市"),null);
city.add(new Option("三明市","三明市"),null);
city.add(new Option("莆田市","莆田市"),null);
city.add(new Option("龙岩市","龙岩市"),null);
break;
case 3:
city.add(new Option("广州市","广州市"),null);
city.add(new Option("东莞市","东莞市"),null);
city.add(new Option("保定市","保定市"),null);
city.add(new Option("珠海市","珠海市"),null);
break;
}
var qu=document.getElementById("qu");
var num1=province.selectedIndex;
qu.options.length=0;
switch(num1){
case 1:
qu.add(new Option("临川区","临川区"),null);
qu.add(new Option("青云谱区","青云谱区"),null);
qu.add(new Option("南昌镇","南昌镇"),null);
qu.add(new Option("云山镇","云山镇"),null);
break;
case 2:
qu.add(new Option("保安县","保安县"),null);
qu.add(new Option("福田区","福田区"),null);
qu.add(new Option("将乐县","将乐县"),null);
qu.add(new Option("厦门区","厦门区"),null);
break;
case 3:
qu.add(new Option("广上县","光上县"),null);
qu.add(new Option("西莞区","西莞区"),null);
qu.add(new Option("三海县","三海县"),null);
qu.add(new Option("广岛区","广岛区"),null);
break;
}
}
</script>-->
</html>