</head>
<script type="text/javascript">
function getResult(stateVal) {
var url = "servlet/SelectCityServlet?state="+stateVal;
if (window.XMLHttpRequest) {
req = new XMLHttpRequest();
}else if (window.ActiveXObject) {
req = new ActiveXObject("Microsoft.XMLHTTP");
}
if(req){
req.open("GET",url, true);
req.onreadystatechange = complete;
req.send(null);
}
}
function complete(){
if (req.readyState == 4) {
if (req.status == 200) {
var city = req.responseXML.getElementsByTagName("city");
//alert(city.length);
var str=new Array();
for(var i=0;i<city.length;i++){
str[i]=city[i].firstChild.data;
}
//alert(document.getElementById("city"));
buildSelect(str,document.getElementById("city"));
}
}
}
function buildSelect(str,sel) {
sel.options.length=0;
for(var i=0;i<str.length;i++) {
sel.options[sel.options.length]=new Option(str[i],str[i])
}
}
function test(){
//alert("test");
}
</script>
<body>
<select name="state" onChange="getResult(this.value)">
<option value="">请选择</option>>
<option value="zj">浙江</option>>
<option value="zs">江苏</option>>
</select>
<select id="city"></select>
</body>
</html>
二、servlet源程序
package com.stephen.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import org.dom4j.*;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* @author stephen
*
* TODO To change the template for this generated type comment go to Window -
* Preferences - Java - Code Style - Code Templates
*/
public class SelectCityServlet extends HttpServlet {
public SelectCityServlet() {
super();
}
public void destroy() {
super.destroy();
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setCharacterEncoding("UTF8");
response.setContentType("text/xml");
response.setHeader("Cache-Control", "no-cache");
String state = request.getParameter("state");
Document document = DocumentHelper.createDocument();
Element root = document.addElement("state");
Element city = null;
if("zj".equals(state)){
city = root.addElement("city");
city.setText("杭州");
city = root.addElement("city");
city.setText("huzhou");
}else{
city = root.addElement("city");
city.setText("南京");
city = root.addElement("city");
city.setText("苏州");
city = root.addElement("city");
city.setText("yangzhou");
}
PrintWriter out=response.getWriter();
String s = root.asXML();
out.write(s);
out.close();
}
}
。