<pre>
<!DOCTYPE html>
<html>
<head>
<title>二级联动.html</title>
<meta name="keywords" content="keyword1,keyword2,keyword3">
<meta name="description" content="this is my page">
<meta name="content-type" content="text/html; charset=UTF-8">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<!--<link rel="stylesheet" type="text/css" href="./styles.css">-->
<script type="text/javascript">
//json对象
// 相当于java当中的map
/*
var json = {"name":"tom","age":18};
//遍历json对象的键
for(var key in json){
//alert(key);
alert(key+"==>"+json[key])
}
*/
//---------------------------------------------------------
var json = {"河北省":["石家庄","廊坊","沧州"],
"山西省":["太原","大同","运城"],
"黑龙江省":["哈尔滨","齐齐哈尔","佳木斯"]};
// 初始化省的下拉选
function fun1(){
//1 获得省的select对象
var province = document.getElementById("province");
//2 遍历json的所有键
for(var key in json){
// 创建一个option
var option = document.createElement("option");
option.innerHTML = key; // <option>河北省</option>
// 将option添加到select中
province.appendChild(option);
}
}
function fun2(){
//1 获得市的select对象
var province = document.getElementById("province");
var city = document.getElementById("city");
//2 清空市级下拉选的数据
city.length =1;
//3 获得用户选择的省
if(province.selectedIndex==0){
//用户选择的是提示选项=>什么也不做
return;
}
//获取省的集合
var options = province.options;
//获取选中省的索引province.selectedIndex
var pName = options[province.selectedIndex].innerHTML;
//4 从json中根据省获得 省下的市数据
var cities = json[pName];
//5 遍历市级的数组
for(var i = 0 ; i<cities.length;i++){
var cityName = cities[i];
//创建市的option
var option = document.createElement("option");
option.innerHTML = cityName;
// 将option添加到select中
city.appendChild(option);
}
}
</script>
</head>
<body onload="fun1();">
<select id="province" onchange="fun2();" >
<option>---请选择省---</option>
</select>
<select id="city" >
<option>---请选择市---</option>
</select>
</body>
</html>
</pre>
