客户端代码
 1     <script> 2         var isie = true; 3         var xmlhttp = null; 4         function createXMLHTTP() {//创建XMLXMLHttpRequest对象 5             if (xmlhttp == null) { 6                 if (window.XMLHttpRequest) { 7                     xmlhttp = new XMLHttpRequest(); 8                 } 9                 else {10                     xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");11                 }12                 //if (xmlhttp == null) {13                 //    alert(‘你的浏览器不支持AJAX‘);14                 //}15             }16         if ($.browser.msie) {//IE浏览器17                 isie = true;18             }19             else {20                 isie = false;21             }22             23         }24         //创建XML文档那个对象,也是第一步25         function createDomXml() {26             var domXml = null;27         //IE浏览器创建xml dom对象28             var signs = ["Msxml2.DOMDocument.5.0", "Msxml2.DOMDocument.4.0", 29 30 "Msxml2.DOMDocument.3.0", "Msxml2.DOMDocument", "Microsoft.XmlDom"];31             for (var i = 0; i < signs.length; i++) {32                 try {33                     domXml = new ActiveXObject(signs[i]);34                     break;35                 }36                 catch (e) { }37             }38         39             //其他浏览器40             if (domXml == null)41                 domXml = document.implementation.createDocument("", "", null);42             return domXml;43         }44         //第二步：客户端获取数据写入xml文档对象里45         function createXml(dom) { 46             var root = doc.createElement("root");//创建根结点47             var assign_id = doc.createElement("id");//子节点48             var assign_ans = doc.createElement("answer");//子节点49             if (isie) {50                 assign_id.text = "1";51                 assign_ans.text = "1";52             }53             else {54                 assign_id.textContent = "1";55                 assign_ans.textContent = "1";56             }57             58             59             root.appendChild(assign_id);60             61             root.appendChild(assign_ans);62             63             dom.appendChild(choose);     64         }65         function submit() {66             var dom = createDomXml();67             createXMLHTTP();68             if (xmlhttp == null) {69                 alert("你的浏览器不支持ajax,请换个浏览器试试");70                 return 0;71             }72             createXml(dom);73             74             xmlhttp.onreadystatechange = success;75             xmlhttp.open("post", "test.aspx", true);//接收请求页面76             //xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");77             xmlhttp.send(dom);78         }79 80         function success()//异步处理函数，当服务成功返回时81         {82             if (xmlhttp.readyState == 4) {83                 alert(xmlhttp.status);84                 if (xmlhttp.status == 200) {85                     alert(xmlhttp.responseText);86                 }87                 else {88                     alert("test error");89                 }90             }91         }92     </script>

服务器端代码 
1   protected void Page_Load(object sender, EventArgs e) 2         { 3         string res; 4             Request.ContentEncoding = System.Text.Encoding.GetEncoding("UTF-8"); 5             XmlDocument xmlDoc = new XmlDocument(); 6             xmlDoc.Load(Request.InputStream); 7             XmlNode node = xmlDoc.SelectSingleNode("choose"); 8             foreach (XmlNode child in node.ChildNodes) 9             {10                 res + child.innerText;11             }12         Response.Write(res);13         Response.End();14         }15     }