Js版：
<!DOCTYPE html>
<html>
<head>
<script>
//1.创建一个二维数组用于存储省份和城市
var cities = new Array(3);
cities[0] = new Array("武汉市","黄冈市","襄阳市","荆州市");
cities[1] = new Array("长沙市","郴州市","株洲市","岳阳市");
cities[2] = new Array("石家庄市","邯郸市","廊坊市","保定市");
cities[3] = new Array("郑州市","洛阳市","开封市","安阳市");
function changeCity(val){
//7.获取第二个下拉列表
var cityEle = document.getElementById("city");
//9.清空第二个下拉列表的option内容
cityEle.options.length=0;
//2.遍历二维数组中的省份
for(var i=0;i<cities.length;i++){
//注意，比较的是角标
if(val==i){
//3.遍历用户选择的省份下的城市
for(var j=0;j<cities[i].length;j++){
//4.创建城市的文本节点
var textNode = document.createTextNode(cities[i][j]);
//5.创建option元素节点
var opEle = document.createElement("option");
//6.将城市的文本节点添加到option元素节点
opEle.appendChild(textNode);
//8.将option元素节点添加到第二个下拉列表中去
cityEle.appendChild(opEle);
}
}
}
}
</script>
</head>
<body>
<select onchange="changeCity(this.value)">
<option>--请选择--</option>
<option value="0">湖北</option>
<option value="1">湖南</option>
<option value="2">河北</option>
<option value="3">河南</option>
</select>
<select id="city">
</select>
</body>
</html>jQuery版：
<script>
$(function(){
//2.创建二维数组用于存储省份和城市
var cities = new Array(3);
cities[0] = new Array("武汉市","黄冈市","襄阳市","荆州市");
cities[1] = new Array("长沙市","郴州市","株洲市","岳阳市");
cities[2] = new Array("石家庄市","邯郸市","廊坊市","保定市");
cities[3] = new Array("郑州市","洛阳市","开封市","安阳市");
$("#province").change(function(){
//10.清除第二个下拉列表的内容
$("#city").empty();
//1.获取用户选择的省份
var val = this.value;
//alert(val);
//3.遍历二维数组中的省份
$.each(cities,function(i,n){
//alert(i+":"+n);
//4.判断用户选择的省份和遍历的省份
if(val==i){
//5.遍历该省份下的所有城市
$.each(cities[i], function(j,m) {
//alert(m);
//6.创建城市文本节点
var textNode = document.createTextNode(m);
//7.创建option元素节点
var opEle = document.createElement("option");
//8.将城市文本节点添加到option元素节点中去
$(opEle).append(textNode);
//9.将option元素节点追加到第二个下拉列表中去
$(opEle).appendTo($("#city"));
});
}
});
});
});
</script>
<select id="province">
<option>--请选择--</option>
<option value="0">湖北</option>
<option value="1">湖南</option>
<option value="2">河北</option>
<option value="3">河南</option>
</select>
<select id="city">
</select>