在注册信息的时候,常常需要通过下拉菜单让用户选择,而且希望用户在第一个下拉框做的选择,影响第二个下拉框的内容。有时候,如果第一个下拉框不作出选择,第二个下拉框根本不会页面上显示,为了给用户呈现一个更清晰的页面。
先来看看效果:

Html源码:
复制代码 代码如下:
<!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>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>动态改变菜单</title>
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript" src="SelectMenu.js"></script>
</head>
<body>
<form action="#">
<br/>
<br/>
<br/>
<div class="Address">
<span class="Province">Province:
<select>
<option value="" selected="selected">Please Choose Province</option>
<option value="HeBei">HeBei</option>
<option value="ShanDong">ShanDong</option>
</select>
</span>
<span class="City" style="display:none">City:
<select>
</select>
</span>
<span class="Area" style="display:none">Area:
<select>
</select>
</span>
<br/>
<br/>
<span class="AddressSelect" style="display:none">
</span>
</div>
</form>
</body>
</html>
Javascript源码
复制代码 代码如下:
$(document).ready(function () {
//找到三个下拉框
var ProvinceSelect = $(".Province").children("select");
var CitySelect = $(".City").children("select");
var AreaSelect = $(".Area").children("select");
var AddressSelect=$(".AddressSelect");
//给第二个下拉框注册事件
ProvinceSelect.change(function () {
//1、获取当前下拉框的值
var ProvinceValue = $(this).val();
//1.1只要第一个下拉框内容有变化,第三个下拉框就要隐藏起来
AreaSelect.parent().hide();
AddressSelect.hide();
AddressSelect.html("");
//2、如果值不为空,则显示城市下拉框
if (ProvinceValue != "") {
CitySelect.html("");
$("<option value=''>Please Choose City</option>").appendTo(CitySelect);
switch(ProvinceValue)
{
//实际项目中,这个城市数组肯定是在服务器获取的,这里为了简便,我就直接自定义了一个数组
//如果追求完美,这里还可以加一道缓存,防止重复获取
case "HeBei":
var CityOfHeBei=["ShiJiaZhuang","CangZhou","LangFang"];
for(var i=0;i<CityOfHeBei.length;i++){
$("<option value='"+CityOfHeBei[i]+"'>"+CityOfHeBei[i]+"</option>").appendTo(CitySelect);
}
break;
case "ShanDong":
var CityOfShanDon=["JiNan","DeZhou","QingDao"];