純JSP+DWR實現(xiàn)三級聯(lián)動下拉選擇菜單實現(xiàn)技巧

?xml version="1.0" encoding="UTF-8"?>
web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
servlet>
servlet-name>dwr-invoker/servlet-name>
servlet-class>
org.directwebremoting.servlet.DwrServlet
/servlet-class>
init-param>
param-name>debug/param-name>
param-value>true/param-value>
/init-param>
/servlet>
servlet>
servlet-name>SelectServlet/servlet-name>
servlet-class>com.action.SelectServlet/servlet-class>
/servlet>
servlet-mapping>
servlet-name>dwr-invoker/servlet-name>
url-pattern>/dwr/*/url-pattern>
/servlet-mapping>
servlet-mapping>
servlet-name>SelectServlet/servlet-name>
url-pattern>/select/url-pattern>
/servlet-mapping>
welcome-file-list>
welcome-file>index.jsp/welcome-file>
/welcome-file-list>
/web-app>

?xml version="1.0" encoding="UTF-8"?>
!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting
2.0//EN" "http://www.getahead.ltd.uk/dwr/dwr20.dtd">
dwr>
!-- 沒有它DWR什么也做不了 -->
allow>
create creator="new" javascript="menu">
param name="class" value="com.dao.CountryDAO" />
/create>
!-- 要轉(zhuǎn)換的Bean -->
convert converter="bean" match="com.vo.Country" />
convert converter="bean" match="com.vo.Province" />
convert converter="bean" match="com.vo.City" />
/allow>
/dwr>

%@ page language="java" import="java.util.*,com.vo.*"
pageEncoding="GBK"%>
%@ taglib uri="http://java.sun.com/jstl/core" prefix="c"%>
html>
head>
title>DWR三級聯(lián)動/title>
script type='text/javascript'
src='/mutiplyMenu/dwr/interface/menu.js'>/script>
script type='text/javascript' src='/mutiplyMenu/dwr/engine.js'>/script>
script type='text/javascript' src='/mutiplyMenu/dwr/util.js'>/script>
/head>
body>
script type="text/javascript">
//根據(jù)國家id查詢所屬省或州
function queryProvince()
{
var countryId = $("country").value;
//默認為不選擇
if(countryId == 0)
{
${"province"}.options.length=0;
${"city"}.options.length=0;
}
else
{
menu.queryProvinceById(countryId,provinceCallback);
}
}
//根據(jù)國家id查詢所屬省或州的回調(diào)函數(shù)
function provinceCallback(provinces)
{
${"province"}.options.length=0;
//每次獲得新的數(shù)據(jù)的時候先把每二個下拉框架的長度清0
for(var i=0;i provinces.length;i ++){
var value = provinces[i].id;
var text = provinces[i].provinceName;
var option = new Option(text, value);
//根據(jù)每組value和text標記的值創(chuàng)建一個option對象
try{
$("province").add(option);//將option對象添加到第二個下拉框中
}catch(e){
}
}
//同時關(guān)聯(lián)第三級
var provinceId = ${"province"}.value;
menu.queryCityById(provinceId,cityCallback);
}
//查詢所屬城市
function queryCity()
{
var provinceId = $("province").value;
menu.queryCityById(provinceId,cityCallback);
}
//查詢所屬城市回調(diào)函數(shù)
function cityCallback(citys)
{
//每次獲得新的數(shù)據(jù)的時候先把每三個下拉框架的長度清0
${"city"}.options.length=0;
for(var i=0;i citys.length;i ++){
var value = citys[i].id;
var text = citys[i].cityName;
var option = new Option(text, value);
//根據(jù)每組value和text標記的值創(chuàng)建一個option對象
try{
$("city").add(option);//將option對象添加到第三個下拉框中
}catch(e){
}
}
}
function change1()
{
queryProvince();
}
function change2()
{
queryCity();
}
/script>
div align="center">
h3>
br>
/h3>
h3>
DWR三級聯(lián)動演示
/h3>
!-- 我都奇怪了，我的c>標簽在這里不能用 -->
select id="country" onchange="change1();">
option selected="selected" value="0">
請選擇
/option>
%
@SuppressWarnings("unchecked")
List list = (List) request.getAttribute("countrys");
for (int i = 0; i list.size(); i++)
{
Country temp = (Country) list.get(i);
%>
option value="%=temp.getId()%>">%=temp.getCountryName()%>/option>
%
}
%>
/select>
select id="province" onchange="change2();">
/select>
select id="city">
/select>
/div>
/body>
/html>