JavaScript Ajax Instance __ajax

The original ecology of simple JavaScript Ajax is only for the record:

Page code

<%@ page language= "java" import= "java.util.*" pageencoding= "UTF-8"%> <% String Path = Request.getcontextpath () 
; 
String basepath = request.getscheme () + "://" +request.getservername () + ":" +request.getserverport () +path+ "/"; %> <! DOCTYPE HTML PUBLIC "-//w3c//dtd HTML 4.01 transitional//en" >  

Background

 
public class Provinceaction extends Action {/* generated Methods//** * Method Execute * @param mapping * @param form * @param request * @param response * @return Actionforward/Public Actionforward Execute ( actionmapping mapping, Actionform form, httpservletrequest request, httpservletresponse response) {//Provinceform 
   
  Provinceform = (provinceform) Form; 
   
  System.out.println ("---------------Province is requested!------------------"); 
   
  String method = Request.getparameter (' method '); 
  String pr[] = {"Beijing", "Tianjin", "Shanghai", "Guangzhou", "Hebei", "Shandong"}; 
  String city[] = {"1", "2", "3", "4", "5", "6"}; 
  StringBuffer sb = new StringBuffer (); if (Method!=null&&method.trim (). Length () >0) {try {Response.setcontenttype () ("Text/xml;charset=utf -8 "); 
    This sentence and the following must not be reversed position, otherwise the page will appear garbled printwriter pw = Response.getwriter (); 
     
    Sb.append ("<?xml version=\" 1.0\ "encoding=\" utf-8\ "?>"); if (Method.equalsignorecase ("innitProvince ")) {sb.append (" <province> "); 
      for (Object obj:pr) {String pro = (string) obj; 
     Sb.append ("<name>" +pro+ "</name>"); 
     } sb.append ("</province>"); 
     Pw.write (Sb.tostring ()); 
    Pw.flush (); 
     else {sb.append ("<province>"); 
      for (Object obj:city) {String pro = (string) obj; 
     Sb.append ("<name>" +pro+ "</name>"); 
     } sb.append ("</province>"); 
     Pw.write (Sb.tostring ()); 
    Pw.flush (); 
   } catch (IOException e) {e.printstacktrace (); 
} return null;  } 
}