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 content="EditPlus®"> <meta content=""> <meta content=""> <meta content=""> <title>Document</title> </head> <body> <select onChange="ck()" > <option>--请选择--</option> </select> <select> <option>--请选择--</option> </select> <select> <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>