联动下拉菜单（jQuery+JSON）
联动下拉菜单
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<script type="text/javascript" src="include/js/jquery.js"></script>
<script type="text/javascript">
$(function(){
$("#city").change(function(){
$.getJSON("option",{index:$(this).val()},function(myJSON){
var myOptions="";
for(var i=0;i<myJSON.length;i++){
myOptions += '<option value="' + myJSON[i].optionValue + '">' + myJSON[i].optionDisplay +
'</option>';
}
$("#area").empty();
$("#area").html(myOptions);
});
});
$("#city").change();
})
</script>
</head>
<body>
This is my JSP page. <br>
<select id="city">
<option value="1">北京</option>
<option value="2">上海</option>
<option value="3">天津</option>
</select>
<select id="area">
</select>
</body>
</html>
package cn.hawk.ajax;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class Option extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/xml");
response.setHeader("Cache-Control", "no-cache");
response.setContentType("text/html; charset=utf-8");
String JSON_text = "";
String city = (String) request.getParameter("index");
System.out.println("城市号："+city);
if(city.equals("1")){
JSON_text = "[{optionValue:'011',optionDisplay:'海淀区'},{optionValue:'012',optionDisplay:'东城区'},{optionValue:'013',optionDisplay:'西城区'}]";
}else if(city.equals("2")){
JSON_text = "[{optionValue:'21',optionDisplay:'闵行区'},{optionValue:'22',optionDisplay:'宝山区'},{optionValue:'23',optionDisplay:'浦东区'}]";
}else if(city.equals("3")){
JSON_text = "[{optionValue:'31',optionDisplay:'和平区'},{optionValue:'32',optionDisplay:'南开区'},{optionValue:'33',optionDisplay:'塘沽区'}]";
}
PrintWriter out = null;
try{
out = response.getWriter();
} catch (IOException ex) {
ex.printStackTrace();
}
out.write(JSON_text);
out.close();
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<servlet-name>Option</servlet-name>
<servlet-class>cn.hawk.ajax.Option</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Option</servlet-name>
<url-pattern>/option</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>