本文實例講述了ajax遍歷xml文檔的方法。分享給大家供大家參考。具體分析如下：
XMLHttpRequest對象提供了兩個可以用來訪問服務器響應的屬性。第一個屬性responseText將響應提供為一個串，第二個屬性 responseXML將響應提供為一個XML對象。一些簡單的用例就很適合按簡單文本來獲取響應，如將響應顯示在警告框中，或者響應只是指示成功還是失 敗的詞
前面<ajax小結>中的例子是從XMLHttpRequest對象獲取服務器響應，並使用XMLHttpRequest對象的responseText屬性將響應獲取為文本。
這次我們來使用XMLHttpRequest對象的responseXML屬性，將結果獲取為XML文檔.這樣一來，我們就可以使用W3C DOM方法來遍歷XML文檔。(前面文章或多或少講過些DOM,在此不重復)
OK,下面來看例子.
首先還是一段XML文檔代碼(parseXML.xml)如下:
parseXML.xml如下：
<?xml version="1.0" encoding="UTF-8"?> <states> <north> <state>Minnesota</state> <state>Iowa</state> <state>North Dakota</state> </north> <south> <state>Texas</state> <state>Oklahoma</state> <state>Louisiana</state> </south> <east> <state>New York</state> <state>North Carolina</state> <state>Massachusetts</state> </east> <west> <state>California</state> <state>Oregon</state> <state>Nevada</state> </west> </states>
MyJsp.jsp如下：
<%@ 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">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'MyJsp.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">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<script type="text/javascript">
var flg=false;
var requestType = "";
//得到XMLHttpRequest對象
function newXMLHttpRequest() {
var xmlreq = false;
if (window.XMLHttpRequest) {
xmlreq = new XMLHttpRequest();
} else if (window.ActiveXObject) {
try {
xmlreq = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e1) {
try {
xmlreq = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e2) {}
}
}
return xmlreq;
}
function startRequest(requestedList){
requestType=requestedList;
flg=newXMLHttpRequest();
//當XMLHttpRequest對象在請求過程中間狀態改變的時候
//回來調用handleStateChange方法
flg.onreadystatechange = handleStateChange;
flg.open("GET", "parseXML.xml", true);
flg.send(null);
}
//處理函數
function handleStateChange(){
if(flg.readyState==4){
if(flg.status==200){
if(requestType=="north"){
listNorthStates();
}else if(requestType=="all"){
listAllStates();
}if(requestType=="south"){
listSouthStates();
}
}
}
}
//用於顯示NorthStates方法
function listNorthStates(){
var xmlDoc=flg.responseXML;
var northNode=xmlDoc.getElementsByTagName("north")[0];
var northStates=northNode.getElementsByTagName("state");
outputList("North States",northStates);
}
//用於顯示SouthStates方法
function listSouthStates(){
var xmlDoc=flg.responseXML;
var SouthNode=xmlDoc.getElementsByTagName("south")[0];
var SouthStates=SouthNode.getElementsByTagName("state");
outputList("South States",SouthStates);
}
//用於顯示AllStates方法
function listAllStates(){
var xmlDoc=flg.responseXML;
var allStates=xmlDoc.getElementsByTagName("state");
outputList("All States in Document", allStates);
}
//輸出元素並顯示於提示框中
function outputList(title,states){
var out=title;
var currState=null;
for(var i=0;i<states.length;i++){
currState=states;
out=out+"\n-"+currState.childNodes[0].nodeValue;
}
alert(out);
}
</script>
<body>
<form action="#">
<input type="button" value="View All Listed States"
onclick="startRequest('all');"/><br>
<input type="button" value="View All Listed Northern States"
onclick="startRequest('north');"/><br>
<input type="button" value="View All Listed Southern States"
onclick="startRequest('south');"/>
</form>
</body>
</html>
希望本文所述對大家的Ajax程序設計有所幫助。