select下拉菜单多级级联效果代码实例
分类：实例代码
使用select下拉菜单经常制作多级级联效果，本章节就以一个省市地区三级级联效果做一下演示。
代码实例如下:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="author" content="http://www.pipipi.net/" />
<title>前端教程网</title>
<script>
//声明省
var pres = ["北京", "上海", "山东"];
//声明市
var cities = [["东城", "昌平", "海淀"],["浦东", "高区"],["济南", "青岛"]];
var areas =
[
[
["东城1", "东城2", "东城3"],
["昌平1", "昌平2", "昌平3"],
["海淀1", "海淀2", "海淀3"]
],
[
["浦东1", "浦东2", "浦东3"],
["高区1", "高区2", "高区3"]
],
[
["济南1", "济南2"],
["青岛1", "青岛2"]
]
]
window.onload=function(){
//设置一个省的公共下标
var pIndex = -1;
var preEle = document.getElementById("pre");
var cityEle = document.getElementById("city");
var areaEle = document.getElementById("area");
//先设置省的值
for (var i = 0; i < pres.length; i++) {
var op = new Option(pres[i], i);
preEle.options.add(op);
}
function chg(obj) {
if (obj.value == -1) {
cityEle.options.length = 0;
areaEle.options.length = 0;
}
//获取值
var val = obj.value;
pIndex = obj.value;
//获取ctiry
var cs = cities[val];
//获取默认区
var as = areas[val][0];
//先清空市
cityEle.options.length = 0;
areaEle.options.length = 0;
for (var i = 0; i < cs.length; i++) {
var op = new Option(cs[i], i);
cityEle.options.add(op);
}
for (var i = 0; i < as.length; i++) {
var op = new Option(as[i], i);
areaEle.options.add(op);
}
}
function chg2(obj) {
var val = obj.selectedIndex;
var as = areas[pIndex][val];
areaEle.options.length = 0;
for (var i = 0; i < as.length; i++) {
var op = new Option(as[i], i);
areaEle.options.add(op);
}
}
preEle.onchange=function(){chg(this)}
cityEle.onchange=function(){chg2(this)}
}
</script>
</head>
<body>
省:<select style="width:100px;" id="pre"><option value="-1">请选择</option></select>
市：<select style="width: 100px;" id="city"></select>
区：<select style="width: 100px;" id="area"></select>
</body>
</html>
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