最近写了一个使用XmlHttpRequest对象调用Web Services 系统时间（分别以GET，POST，SOAP 1.1，SOAP 1.2方式），通过XML DOM对象解析返回 的小程序，兼容IE 和 FireFox浏览器 希望对初学AJAX的朋友带来帮助 不过程序中还有很多不足的地方，还请多多指点... 谢谢~
首先我们需要了解XmlHttpRequest对象使用的基本步骤：
1.创建XMLHttpRequest对象
2.创建HTTP请求
3.设置状态改变时的事件
4.发送HTTP请求
5.获取异步返回的数据
一、GetSystemTime.htm 页面如下：
代码：
Code<body>
<p>
使用<span>XmlHttpRequest</span>对象调用<span>Web Services</span>，并使用<span>XML DOM</span>
对象解析返回，兼容IE 和 FireFox浏览器
</p>
<div style="padding-right: 20px;">
<select id="select">
<option selected="selected" value="0">HTTP GET</option>
<option value="1">HTTP POST</option>
<option value="2">SOAP 1.1</option>
<option value="3">SOAP 1.2</option>
</select>
<input type="button" onclick="GetTime();" value="调用Web Service" />
<input type="button" value="刷新界面" onclick="RenovatePage();" />
<span style="margin-left: 40px;"><span style="color: Blue;">系统时间为：</span>
<input type="text" id="serverTime" style="background-color: #FFF9c4;" /></span>
<div id="loading" style="display: none;">
<img alt="load" src="images/loading.gif" style="float: left; padding: 0 10px 0 0;" />
<span style="color: #A11111">正在加载数据
</span></div>
</div>
<br />
<textarea id="response" style=" 750px; height: 150px; font-family: Courier New;
background-color: #FFF9c4; font-size: 14px; margin-top: 0px;" cols="25" rows="10"></textarea><br />
</body>
二、调用页面的Js代码：
Code1
var XHR;2
var getMode; //调用WebServices方式3
var xmlString; // 传入Xml字符串类型4
var ctype = null;5
var soapheader = null;6
var data = null;7
var newDom = null;8
var res = null;9
10
//创建xmlHttpRequest对象11
function CreatXHR() {12
try {13
//适用于IE5.0 或IE6.014
XHR = new ActiveXObject("Msxml2.XMLHTTP");15
}16
catch (e) {17
try {18
//用于IE5.0下19
XHR = new ActiveXObject("Microsoft.XMLHTTP");20
}21
catch (e) {22
XHR = false;23
}24
}25
if (!XHR && typeof (XMLHttpRequest) != "undefined") {26
//适用于IE7.0或FireFox27
XHR = new XMLHttpRequest();28
}29
}Code1
//调用函数2
function onReadyStateChange() {3
var res = null;4
if (XHR.readyState == 4) {5
if (XHR.status == 200) {6
document.getElementById("response").value = "这是返回的响应正文：\r\n" + XHR.responseText;7
//调用XML DOM函数使用xpath及命名空间映射实现数据查询8
res = HandleResponseByXMLDOM(XHR.responseText, data, nsMap);9
}10
document.getElementById("serverTime").value = res;11
}12
}13
//根据页面单选框的选项调用Webservice14
function GetTime() {15
getMode = document.getElementById("select").value; //从单选框中获取调用服务类型16
InvokeWebService(getMode, "Service.asmx", "http://www.SouBao.com", "GetTime"); //调用webservice服务17
}Code1
/**//*---------------------------------------------------------------2
调用Webservice服务3
mode：指调用服务的类型[get,post,soap1.1,soap1.2]4
url:指调用webservice的文件地址5
nspace： Services的namespace，默认为null6
MethodName：webservice的方法名7
-----------------------------------------------------------------*/8
function InvokeWebService(mode, url, nspace, MethodName) {9
10
var method = "POST"; //调用方法11
//调用之前显示动画12
document.getElementById("loading").style.display = "none";13
switch (mode) {14
// GET 15
case "0":16
method = "GET";17
//由于缓存的原因，用了个取巧的办法：使用一个时间戳 ['不是原创~！']18
url = url + "/" + MethodName + "?" + new Date();19
break;20
// POST 21
case "1":22
url = url + "/" + MethodName;23
break;24
//SOAP 1.1 25
case "2":26
//设置Content-Type报头27
ctype = "text/xml; charset=utf-8";28
//设置SOAPAction报头29
soapheader = nspace + "/" + MethodName;30
url = url + "?.tmp=" + new Date() + "/" + MethodName;31
32
data = "<?xml version=\"1.0\" encoding=\"utf-8\"?>";33
data += "\r\n" + "<soap:Envelope xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\">";34
data += "\r\n" + "<soap:Body>"35
data += "\r\n" + "<" + MethodName + " xmlns=\"" + nspace + "\" />";36
data += "\r\n" + "</soap:Body>";37
data += "\r\n" + "</soap:Envelope>";38
break;39
//SOAP 1.2 40
case "3":41
ctype = "application/soap+xml; charset=utf-8";42
//构建最终请求的url地址43
url = url + "?.tmp=" + new Date() + "/" + MethodName;44
data = "<?xml version=\"1.0\" encoding=\"utf-8\"?>";45
data += "\r\n" + "<soap12:Envelope xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" xmlns:soap12=\"http://www.w3.org/2003/05/soap-envelope\">";46
data += "\r\n" + "<soap12:Body>"47
data += "\r\n" + "<" + MethodName + " xmlns=\"" + nspace + "\" />";48
data += "\r\n" + "</soap12:Body>";49
data += "\r\n" + "</soap12:Envelope>";50
break;51
}52
//显示加载53
document.getElementById("loading").style.display = "block";54
//调用Web Services55
//Load(method, url, onReadyStateChange, data, ctype, soapheader);56
document.getElementById("response").value = "";57
//延时1S58
setTimeout(function() { Load(method, url, onReadyStateChange, data, ctype, soapheader); }, 1000);59
}
Code1
function Load(method, url, onReadyStateChange, data, ctype, soapheader) {2
if (ctype == null) {3
ctype = "application/x-www-form-urlencoded; charset=utf-8";4
}5
//创建XMLHttpRequest对象6
CreatXHR();7
//创建HTTP请求8
XHR.open(method, url, true);9
XHR.setRequestHeader("Content-Type", ctype);10
if (soapheader != null) {11
XHR.setRequestHeader("SOAPAction", soapheader);12
}13
XHR.onreadystatechange = onReadyStateChange;14
XHR.send(data);15
}16
17
//调用函数18
function onReadyStateChange() {19
20
if (XHR.readyState == 4) {21
document.getElementById("loading").style.display = "none";22
if (XHR.status == 200) {23
document.getElementById("response").value = "这是返回的响应正文：\r\n" + XHR.responseText;24
//alert(XHR.responseText);25
res = XMLDOM(XHR.responseText);26
}27
document.getElementById("serverTime").value = res;28
}29
}30
1
//创建XmlDom对象2
function CreatXmlDoom(xmlString) {3
//判断是否为IE浏览器 （IE不支持DOMparser对象）4
if (!window.DOMParser) {5
var progIDs = ["Msxml2.DOMDocument.3.0", "Msxml2.DOMDocument"];6
for (var i = 0; i < progIDs.length; i++) {7
try {8
var xmlDOM = new ActiveXObject(progIDs[i]);9
xmlDOM.async = false;10
xmlDOM.setProperty("SelectionLanguage", "XPath");11
xmlDOM.loadXML(xmlString);12
return xmlDOM;13
}14
catch (ex) {15
alert(ex);16
}17
}18
return null;19
}20
else {21
try {22
var domParser = new DOMParser();23
newDom = domParser.parseFromString(xmlString, "text/xml");24
//alert(newDom.childNodes.length);25
return newDom;26
27
}28
catch (ex) {29
alert(ex);30
}31
}32
}33
//定义了一个FireFox 找到节点34
function FFParser() {35
try {36
var domParser = new DOMParser();37
var newDom = domParser.parseFromString(xmlString, "text/xml");38
// alert(newDom.childNodes.length);39
return newDom;40
41
}42
catch (ex) {43
alert(ex);44
}45
}Code1
//传入XML字符串2
3
function XMLDOM(responseString) {4
//传入xml字符串，生成XML DOM对象5
var oXmlDom = CreatXmlDoom(responseString);6
//若是IE浏览器 “ typeof(DOMParser)=="undefined"”这里也无法使用咯 也可以使用doucment.all7
if (!window.DOMParser) {8
oXmlDom.setProperty("SelectionNamespaces", "xmlns:a=\"http://www.SouBao.com\"");9
try {10
//执行Xpath查询11
if (getMode < 2) {12
// var oResults = oXmlDom.getElementsByTagName("string");13
var oResults = oXmlDom.selectNodes("/a:string");14
}15
//在这个地方无法selectNodes 找到节点 很奇怪咯~~！ 【 命名空间的问题咯 已经解决~~~！！！】16
// else {17
// var oResults = oXmlDom.selectNodes("/soap:Envelope/soap:Body/GetTimeResponse/GetTimeResult");18
//}19
else {20
var oResults = oXmlDom.getElementsByTagName("GetTimeResult");21
}22
if (oResults != null) {23
//读出第一个结点24
return oResults[0].childNodes[0].nodeValue;25
}26
}27
catch (ex) {28
alert(ex);29
return null;30
}31
}32
else {33
var oEval = new XPathEvaluator();34
var xpath = null;35
36
try {37
if (getMode < 2) {38
xpath = "/a:string";39
}40
else {41
xpath = "/soap:Envelope/soap:Body/a:GetTimeResponse/GetTimeResult";42
}43
44
//同步45
// XmlDoc.async = false;46
//XmlDoc.load(responseString);47
var oEvaluator = new XPathEvaluator();48
var oResults = oEvaluator.evaluate(xpath, newDom, nsResolver, XPathResult.ANY_TYPE, null);49
//alert(oResults);50
//若结果不为空51
if (oResults != null) {52
var onode = oResults.iterateNext();53
54
// while (onode != null) {55
//alert(onode.childNodes[0].nodeValue);56
return onode.childNodes[0].nodeValue;57
//document.getElementById("serverTime").value = res;58
// document.getElementById("loading").style.display = "none";59
60
//在结果集合中选择下一节点61
// onode = oResults.iterateNext();62
// }63
}64
}65
66
catch (ex) {67
68
}69
}70
//return null;71
}72
73
//命名空间映射函数74
function nsResolver(prefix) {75
var ns =76
{77
"a": "http://www.SouBao.com",78
"b": "http://ccniit.com"79
};80
return ns[prefix] || null;81
}82
// 刷新界面83
function RenovatePage() {84
85
86
window.location.reload(); //刷新操作87
// 这个只是针对FireFox浏览器88
document.getElementById("response").value = "";89
document.getElementById("serverTime").value = "";90
91
92
}三、调用Web Services 服务：
Code1
/**//// <summary>2
///Service 的摘要说明3
/// </summary>4
[WebService(Namespace = "http://www.SouBao.com")]5
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]6
public class Service : System.Web.Services.WebService {7
8
public Service () {9
10
//如果使用设计的组件，请取消注释以下行 11
//InitializeComponent(); 12
}13
14
[WebMethod]15
public string GetTime() 16
{17
return DateTime.Now.ToString();18
}19
20
}