二級聯(lián)動菜單代碼(AJAX+JAVA)做項目經(jīng)常要用到的,現(xiàn)在只給出一個不用數(shù)據(jù)庫的代碼,可作參考:
/**
*category.jsp 含有AJAX程序
*
*/
[java]
<%@ page language="java" pageEncoding="UTF-8"%>
<html>
<head>
<title>二級菜單聯(lián)動演示</title>
<script type="text/javascript">
var req;
window.onload=function(){//頁面加載時的函數(shù)
}
function Change_Select(){//當?shù)谝粋€下拉框的選項發(fā)生改變時調(diào)用該函數(shù)
var zhi = document.getElementById('hero').value;
var url = "servlet/select?id="+ escape(zhi);
if(window.XMLHttpRequest){
req = new XMLHttpRequest();
}else if(window.ActiveXObject){
req = new ActiveXObject("Microsoft.XMLHTTP");
}
if(req){
req.open("GET",url,true);
req.onreadystatechange = callback; //指定回調(diào)函數(shù)為callback
req.send(null);
}
}
function callback(){
if(req.readyState ==4){
if(req.status ==200){
parseMessage();//解析XML文檔
}else{
alert("Not able to retrieve description" + req.statusText);
}
}
}
function parseMessage(){
var xmlDoc = req.responseXML.documentElement;//獲得返回的XML文檔
var xSel = xmlDoc.getElementsByTagName('select');
//獲得XML文檔中的所有<select>標記
var select_root = document.getElementById('skill');
//獲得網(wǎng)頁中的第二個下拉框
select_root.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<xSel.length;i++){
var xValue = xSel[i].childNodes[0].firstChild.nodeValue;
//獲得每個<select>標記中的第一個標記的值,也就是<value>標記的值
var xText = xSel[i].childNodes[1].firstChild.nodeValue;
//獲得每個<select>標記中的第二個標記的值,也就是<text>標記的值
var option = new Option(xText, xValue);
//根據(jù)每組value和text標記的值創(chuàng)建一個option對象
try{
select_root.add(option);//將option對象添加到第二個下拉框中
}catch(e){
}
}
}
</script>
</head>
<body>
<div align="center">
<form name="form1" method="post" action="">
<table width="70%" border="0" cellspacing="0" cellpadding="0">
<tr>
<td align="center">Double Select Box</td>
</tr>
<tr>
<td>
<select name="hero" id="hero" onChange="Change_Select()">
<!--第一個下拉菜單-->
<option value="0">Unbounded</option>
<option value="1">D.K. </option>
<option value="2">NEC. </option>
<option value="3">BOSS </option>
</select>
<select name="skill" id="skill">
<!--第二個下拉菜單-->
<option value="0">Unbounded</option>
</select>
</td>
</tr>
<tr>
<td> </td>
<tr>
</table>
</form>
</div>
</body>
</html>
[/java]
2007-3-27 15:02 bufegar
/**
*web.xml 配置Servlet,可以使用MyEclipse創(chuàng)建Servlet,自動生成web.xml
*
*/
[xml]
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="<a target="_blank">[url]http://java.sun.com/xml/ns/j2ee[/url]"</a> xmlns:xsi="<a target="_blank">[url]http://www.w3.org/2001/XMLSchema-instance[/url]"</a> version="2.4" xsi:schemaLocation="<a target="_blank">[url]http://java.sun.com/xml/ns/j2ee[/url]</a> <a target="_blank">[url]http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd[/url]"></a>
<servlet>
<servlet-name>select</servlet-name>
<servlet-class>onlinetest.servlet.SelectServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>select</servlet-name>
<url-pattern>/servlet/select</url-pattern>
</servlet-mapping>
<filter>
<filter-name>characterFilter</filter-name>
<filter-class>filters.SetCharacterEncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>utf-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>characterFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
</web-app>[/xml]
原文地址:[url]http://my.boolean.cn/read.php?130&part=3[/url]