本文实例讲述了javascript基于DOM实现省市级联下拉框的方法。分享给大家供大家参考。具体实现方法如下：
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>省市级联下拉框</title>
<script type="text/javascript">
var provs = { "江西省": ["南昌市", "景德镇", "九江", "鹰潭", "萍乡", "新馀", "赣州", "吉安", "宜春", "抚州", "上饶"],
"福建省": ["福州", "厦门", "莆田", "三明", "泉州", "漳州", "南平", "龙岩", "宁德"],
"河北省": ["石家庄", "邯郸", "邢台", "保定", "张家口", "承德", "廊坊", "唐山", "秦皇岛", "沧州", "衡水"]
};
function loadProv() {
//加载省份数据
var prov = document.getElementById("prov");
for (var key in provs) {
var provName = key;
var optProv = document.createElement("option");
optProv.value = provName;
optProv.innerText = provName;
prov.appendChild(optProv);
}
}
function provChange() {
var prov = document.getElementById("prov");
var city = document.getElementById("city");
var provName = prov.value;
//如果没有选择省份，则把城市下拉框隐藏
if (provName == "none") {
city.style.display = "none";
return;
}
else {
city.style.display = "";
}
var citys = provs[provName];
//city.options.length = 0;
//用这种方法也可以清空原始列表
//清空城市的原始数据
for (var i = city.childNodes.length - 1; i >= 0; i--) {
var child = city.childNodes[i];
city.removeChild(child);
}
//添加新的城市数据
for (var i = 0; i < citys.length; i++) {
var optCity = document.createElement("option");
optCity.value = citys[i];
optCity.innerText = citys[i];
city.appendChild(optCity);
}
}
</script>
</head>
<body onload="loadProv()">
<select id="prov" onchange="provChange()">
<option value="none">请选择省</option>
</select>
<select id="city" style="display:none"></select>
</body>
</html>
希望本文所述对大家的javascript程序设计有所帮助。
