<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>省市级联</title>
<script type="text/javascript">
window.onload = function () {
var datas = { "山东": ["青岛", "济南", "烟台"], "山西": ["大同", "太原", "运城"], "湖北": ["武汉", "咸宁", "宜昌"] };
var s1obj = document.getElementById('s1');
//动态创建数据,加载到省中.
//假定
var defaultProvice = '山西';
//1加载省份
for (var shen in datas) {
//1.1创建一个select下的option.
var optshen = document.createElement('option');
optshen.innerHTML = shen;
optshen.value = shen;
//1.2设置默认.
if (shen == defaultProvice) {
optshen.selected = true;
}
s1obj.appendChild(optshen);
}
//2.设置默认的省下的城市.
//2.1获取默认的省份下的城市.
var citys = datas[defaultProvice];
//2.2.获取s2
var s2obj = document.getElementById('s2');
for (var i = 0; i < citys.length; i++) {
//2.3 创建一个option
var optcity = document.createElement('option');
optcity.innerHTML = citys[i];
optcity.value = citys[i];
s2obj.appendChild(optcity);
}
//3为省份的select元素注册一个onchange事件.
s1obj.onchange = function () {
//4.清空城市选中列表
while (s2obj.firstChild) {
s2obj.removeChild(s2obj.firstChild);
}
//4方法二
// s2obj.innerHTML = '';
//1.获取当前选中项的名称.
var provinceName = this.value;
var currentCitys = datas[provinceName];
//创建option
for (var i = 0; i < currentCitys.length; i++) {
//3.1
var optionCity = document.createElement('option');
optionCity.value = currentCitys[i];
optionCity.innerHTML = currentCitys[i];
s2obj.appendChild(optionCity);
}
}
}
</script>
</head>
<body>
省<select id="s1"></select>
市<select id="s2"></select>
</body>
</html>