在异步应用程序中发送和接收信息时，常见的可以选择以纯文本和XML作为数据格式（您可以参考jquery下的ajax）,现在还有一种比较流行的方式：JSON（JavaScript Object Notation）。好了，下面举例说明这三种数据格式在ajax的异步应用。
一、纯文本方式
1、发送/接收数据：
Code is cheap.看代码：
Code
/*testJs.js*/
// 此函数等价于document.getElementById /document.all
function $(s) { if (document.getElementById) { return eval(\'document.getElementById("\' + s + \'")\'); } else { return eval(\'document.all.\' + s); } }
// 创建 XMLHttpRequest对象，以发送ajax请求
function createXMLHTTP() {
var xmlHttp = false;
var arrSignatures = ["MSXML2.XMLHTTP.5.0", "MSXML2.XMLHTTP.4.0",
"MSXML2.XMLHTTP.3.0", "MSXML2.XMLHTTP",
"Microsoft.XMLHTTP"];
for (var i = 0; i < arrSignatures.length; i++) {
try {
xmlHttp = new ActiveXObject(arrSignatures[i]);
return xmlHttp;
}
catch (oError) {
xmlHttp = false; //ignore
}
}
// throw new Error("MSXML is not installed on your system.");
if (!xmlHttp && typeof XMLHttpRequest != \'undefined\') {
xmlHttp = new XMLHttpRequest();
}
return xmlHttp;
}
var xmlReq = createXMLHTTP();
// 发送ajax处理请求(这里简单验证用户名和密码的有效性，默认正确的输入：用户名和密码都是test)
function validatePwd(oTxt) {
var url = "/AjaxOperations.aspx";
xmlReq.open("post", url, true);
xmlReq.setRequestHeader("Content-Length", oTxt.value.length + $("txtUserName").value.length);
xmlReq.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
xmlReq.onreadystatechange = callBack;
xmlReq.send("action=chkPwd&userInfos=" + escape(oTxt.value + "/" + $("txtUserName").value)); // 发送文本
}
function callBack() {
if (xmlReq.readyState == 4) {
if (xmlReq.status == 200) {
alert(xmlReq.responseText); // 接收文本
}
else if (xmlReq.status == 404) {
alert("Requested URL is not found.");
} else if (xmlReq.status == 403) {
alert("Access denied.");
} else
alert("status is " + xmlReq.status);
}
}
几个附加文件源码：
Code
//jsTest.htm
<html>
<head>
<title>js test</title>
<script src="js/testJs.js" type="text/javascript"></script>
</head>
<body>
<form id="form1">
<div>
用户名：<input id="txtUserName" name="txtUserName" type="text" /> 密码：<input id="txtPwd" name="txtPwd" type="password" onblur="validatePwd(this)" /></div>
</form>
</body>
</html>
//AjaxOperations.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="AjaxOperations.aspx.cs" Inherits="WebTest2008.AjaxOperations" %>
// AjaxOperations.aspx.cs
using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace WebTest2008
{
public partial class AjaxOperations : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!string.IsNullOrEmpty(Request["action"]) && Request["action"] == "chkPwd")
{
string responseTxt = "用户名和密码不匹配！";
string tempStr = Request["userInfos"];
/* 测试用 实际项目中可以对数据库进行检索等等相关操作，这里简化了 */
if (tempStr.Split(new char[] { \'/\' }, StringSplitOptions.RemoveEmptyEntries)[0] == "test" && tempStr.Split(new char[] { \'/\' }, StringSplitOptions.RemoveEmptyEntries)[1] == "test")
{
responseTxt = "验证通过！";
}
Response.Write(responseTxt);
}
}
}
}
一一保存文件，ctrl+F5，运行试试看吧。
上面这种方式是最简单最直接也是最有效的方式。熟练使用最佳。
二、XML方式
1、发送XML数据
Code
//testJs.js
// 此函数等价于document.getElementById /document.all
function $(s) { if (document.getElementById) { return eval(\'document.getElementById("\' + s + \'")\'); } else { return eval(\'document.all.\' + s); } }
// 创建 XMLHttpRequest对象，以发送ajax请求
function createXMLHTTP() {
var xmlHttp = false;
var arrSignatures = ["MSXML2.XMLHTTP.5.0", "MSXML2.XMLHTTP.4.0",
"MSXML2.XMLHTTP.3.0", "MSXML2.XMLHTTP",
"Microsoft.XMLHTTP"];
for (var i = 0; i < arrSignatures.length; i++) {
try {
xmlHttp = new ActiveXObject(arrSignatures[i]);
return xmlHttp;
}
catch (oError) {
xmlHttp = false; //ignore
}
}
// throw new Error("MSXML is not installed on your system.");
if (!xmlHttp && typeof XMLHttpRequest != \'undefined\') {
xmlHttp = new XMLHttpRequest();
}
return xmlHttp;
}
var xmlReq = createXMLHTTP();
// 发送ajax处理请求(这里简单验证用户名和密码的有效性，默认正确的输入：用户名和密码都是test)
function validatePwd(oTxt) {
var url = "/AjaxOperations.aspx?action=xmlOp";
var xmlStr = "<profile>" +
" <userName>" + escape($("txtUserName").value) + "</userName>" +
" <userPwd>" + escape($("txtPwd").value) + "</userPwd>" +
"</profile>";
xmlReq.open("post", url, true);
// Tell the server you\'re sending it XML
xmlReq.setRequestHeader("Content-Type", "text/xml"); // 这里注意
xmlReq.onreadystatechange = callBack;
xmlReq.send(xmlStr); // 发送XML
}
function callBack() {
if (xmlReq.readyState == 4) {
if (xmlReq.status == 200) {
alert(xmlReq.responseText); // 接收文本
}
else if (xmlReq.status == 404) {
alert("Requested URL is not found.");
} else if (xmlReq.status == 403) {
alert("Access denied.");
} else
alert("status is " + xmlReq.status);
}
}jsTest.htm文件不变，AjaxOperations.aspx的HTML文件内容不变，服务器端.CS处理代码如下：
Code
// AjaxOperations.aspx.cs
using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Xml;
namespace WebTest2008
{
public partial class AjaxOperations : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!string.IsNullOrEmpty(Request["action"]) && Request["action"] == "xmlOp") // 处理xml
{
XmlDocument doc = new XmlDocument();
try
{
doc.Load(Request.InputStream); //获取xml数据(这里需要注意接受xml数据的方法)
}
catch (Exception ex)
{
throw ex;
}
string responseTxt = "";
string tempName = doc.SelectSingleNode("profile/userName").InnerText;
string tempPwd = doc.SelectSingleNode("profile/userPwd").InnerText;
if (tempName == "test" && tempPwd == "test")
{
responseTxt = "验证通过！";
}
else responseTxt = "验证失败！";
Response.Write(responseTxt); // 写文本
}
}
}
}
很简单的代码，运行看看吧。
2、接收XML数据：
我们看到，上面两个.js文件里处理返回数据时都用到了xmlReq.responseText的属性，下面我们试试看xmlReq.responseXML属性：
Code
//testJs.js
// 此函数等价于document.getElementById /document.all
function $(s) { if (document.getElementById) { return eval(\'document.getElementById("\' + s + \'")\'); } else { return eval(\'document.all.\' + s); } }
// 创建 XMLHttpRequest对象，以发送ajax请求
function createXMLHTTP() {
var xmlHttp = false;
var arrSignatures = ["MSXML2.XMLHTTP.5.0", "MSXML2.XMLHTTP.4.0",
"MSXML2.XMLHTTP.3.0", "MSXML2.XMLHTTP",
"Microsoft.XMLHTTP"];
for (var i = 0; i < arrSignatures.length; i++) {
try {
xmlHttp = new ActiveXObject(arrSignatures[i]);
return xmlHttp;
}
catch (oError) {
xmlHttp = false; //ignore
}
}
// throw new Error("MSXML is not installed on your system.");
if (!xmlHttp && typeof XMLHttpRequest != \'undefined\') {
xmlHttp = new XMLHttpRequest();
}
return xmlHttp;
}
var xmlReq = createXMLHTTP();
// 发送ajax处理请求(这里简单验证用户名和密码的有效性，默认正确的输入：用户名和密码都是test)
function validatePwd(oTxt) {
var url = "/AjaxOperations.aspx?action=xmlOp";
var xmlStr = "<profile>" +
" <userName>" + escape($("txtUserName").value) + "</userName>" +
" <userPwd>" + escape($("txtPwd").value) + "</userPwd>" +
"</profile>";
xmlReq.open("post", url, true);
// Tell the server you\'re sending it XML
xmlReq.setRequestHeader("Content-Type", "text/xml");
xmlReq.onreadystatechange = callBack;
xmlReq.send(xmlStr); // 发送XML
}
function callBack() {
if (xmlReq.readyState == 4) {
if (xmlReq.status == 200) {
var xmlDoc = xmlReq.responseXML; // 接收XML
// var nodes = xmlDoc.childNodes;
// alert("文件根标签的名称： " + xmlDoc.documentElement.tagName);
// alert("根元素共有子节点个数: " + xmlDoc.documentElement.childNodes.length);
alert(xmlDoc.documentElement.childNodes(0).text);
}
else if (xmlReq.status == 404) {
alert("Requested URL is not found.");
} else if (xmlReq.status == 403) {
alert("Access denied.");
} else
alert("status is " + xmlReq.status);
}
}
同样，jsTest.htm文件不变，AjaxOperations.aspx的HTML文件内容不变，服务器端.CS处理代码稍作修改如下：
Code
using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Xml;
namespace WebTest2008
{
public partial class AjaxOperations : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!string.IsNullOrEmpty(Request["action"]) && Request["action"] == "xmlOp") // 处理xml
{
XmlDocument doc = new XmlDocument();
try
{
doc.Load(Request.InputStream); //获取xml数据
}
catch (Exception ex)
{
throw ex;
}
string responseXmlTxt = "";
string tempName = doc.SelectSingleNode("profile/userName").InnerText;
string tempPwd = doc.SelectSingleNode("profile/userPwd").InnerText;
if (tempName == "test" && tempPwd == "test")
{
responseXmlTxt = "<?xml version=\"1.0\" encoding=\"utf-8\" ?> <msg>验证通过！</msg>"; // 测试用，简单的xml文件
}
else responseXmlTxt = "<?xml version=\"1.0\" encoding=\"utf-8\" ?><msg>验证失败！</msg>";
Response.ContentType = ("text/xml;charset=UTF-8"); // 这里必须要设置，否则客户端接收不到这里写好的xml文件
Response.Write(responseXmlTxt); // 写xml
Response.End();
}
}
}
}
Code
function testJson() {
//定义一个user(json的格式,其实就是定义一个js函数(变量)的方式而已)
var user =
{
"username": "jeff wong",
"age": 25,
"info": { "tel": "12345678", "cellphone": "13312345678" },
"address": // 数组
[
{ "city": "beijing", "postcode": "101110" },
{ "city": "ny city", "postcode": "911119" }
]
}
alert(user.username);
alert(user.age);
alert(user.info.cellphone);
alert(user.address[0].city);
alert(user.address[0].postcode);
user.username = "xiao wang";
alert(user.username);
}
Code
function Car(maker, model, year, color) {
this.maker = maker;
this.model = model;
this.year = year;
this.color = color;
}
function testJson() {
var tempCar = new Car("VW", "S", 1999, "yellow");
alert(tempCar.toJSONString());
}也可以使用eval或者parseJSON()方法来转换json数据到object：
Code
function testJson() {
var str = \'{ "name": "jeff wong", "age": 25,"address":"beijing"}\';
var tempObj = eval(\'(\' + str + \')\');
alert(tempObj.toJSONString()); //使用eval方法
var tempObj1 = str.parseJSON();
alert(tempObj1.toJSONString()); // 或者使用parseJSON()方法
}关于json.js的学习，请参考网上其他资源，这里我不再赘述了。说了这么多，实践环节开始了：
Code
// 此函数等价于document.getElementById /document.all
function $(s) { if (document.getElementById) { return eval(\'document.getElementById("\' + s + \'")\'); } else { return eval(\'document.all.\' + s); } }
// 创建 XMLHttpRequest对象，以发送ajax请求
function createXMLHTTP() {
var xmlHttp = false;
var arrSignatures = ["MSXML2.XMLHTTP.5.0", "MSXML2.XMLHTTP.4.0",
"MSXML2.XMLHTTP.3.0", "MSXML2.XMLHTTP",
"Microsoft.XMLHTTP"];
for (var i = 0; i < arrSignatures.length; i++) {
try {
xmlHttp = new ActiveXObject(arrSignatures[i]);
return xmlHttp;
}
catch (oError) {
xmlHttp = false; //ignore
}
}
// throw new Error("MSXML is not installed on your system.");
if (!xmlHttp && typeof XMLHttpRequest != \'undefined\') {
xmlHttp = new XMLHttpRequest();
}
return xmlHttp;
}
var xmlReq = createXMLHTTP();
// 发送ajax处理请求(这里简单验证用户名和密码的有效性，默认正确的输入：用户名和密码都是test)
function validatePwd(oTxt) {
var url = "/AjaxOperations.aspx?action=jsonOp";
// JSON就只是文本,由于不需要特殊编码而且每个服务器端脚本都能处理文本数据，所以可以轻松利用JSON并将其应用到服务器。
var str = \'{ "userName":"\' + $("txtUserName").value + \'", "userPwd": "\' + $("txtPwd").value + \'"}\';
var jsonStr = str.parseJSON().toJSONString(); // you\'re sending it JSON
xmlReq.open("post", url, true);
xmlReq.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
xmlReq.onreadystatechange = callBack;
xmlReq.send("sendStr=" + jsonStr); // 发送JSON(在服务器上解释JSON)
}
function callBack() {
if (xmlReq.readyState == 4) {
if (xmlReq.status == 200) {
var jsonStr = xmlReq.responseText.parseJSON().toJSONString(); //转化为json数据
alert(jsonStr);
}
else if (xmlReq.status == 404) {
alert("Requested URL is not found.");
} else if (xmlReq.status == 403) {
alert("Access denied.");
} else
alert("status is " + xmlReq.status);
}
}附加文件，AjaxOperations.aspx的html页面没有改变，AjaxOperations.aspx.cs代码稍作调整如下：
Code
using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace WebTest2008
{
public partial class AjaxOperations : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!string.IsNullOrEmpty(Request["action"]) && Request["action"] == "jsonOp") // 处理JSON
{
string responseJsonTxt = "";
string tempStr = Request["sendStr"].Trim(new char[] { \'{\', \'}\' }); // 在服务器上解释JSON需要引用一个能够转化JSON的组件:Json.Net,这里简单测试，略过Json.Net
if (tempStr.Split(new char[] { \',\' })[0].Split(new char[] { \':\' })[1] == "\"test\"" && tempStr.Split(new char[] { \',\' })[1].Split(new char[] { \':\' })[1] == "\"test\"")
{
responseJsonTxt = "{\"msg\":\"验证通过！\"}"; // 测试用
}
else responseJsonTxt = "{\"msg\":\"验证失败！\"}";
Response.Write(responseJsonTxt);
Response.End();
}
}jsTest.html引入json.js文件（必须下载json.js文件，否则js报错），如下：
Code
<html>
<head>
<title>js test</title>
<script src="js/json.js" type="text/javascript"></script>
<script src="js/testJs.js" type="text/javascript"></script>
</head>
<body>
<form id="form1">
<div>
用户名：<input id="txtUserName" name="txtUserName" type="text" />
密码：<input id="txtPwd" name="txtPwd" type="password" onblur="validatePwd(this)" /></div>
</form>
</body>
</html>
json入门学习就到这里了。希望这篇入门文章对你有帮助。
一、纯文本方式
1、发送/接收数据：
Code is cheap.看代码：
Code/*testJs.js*/
// 此函数等价于document.getElementById /document.all
function $(s) { if (document.getElementById) { return eval(\'document.getElementById("\' + s + \'")\'); } else { return eval(\'document.all.\' + s); } }
// 创建 XMLHttpRequest对象，以发送ajax请求
function createXMLHTTP() {
var xmlHttp = false;
var arrSignatures = ["MSXML2.XMLHTTP.5.0", "MSXML2.XMLHTTP.4.0",
"MSXML2.XMLHTTP.3.0", "MSXML2.XMLHTTP",
"Microsoft.XMLHTTP"];
for (var i = 0; i < arrSignatures.length; i++) {
try {
xmlHttp = new ActiveXObject(arrSignatures[i]);
return xmlHttp;
}
catch (oError) {
xmlHttp = false; //ignore
}
}
// throw new Error("MSXML is not installed on your system.");
if (!xmlHttp && typeof XMLHttpRequest != \'undefined\') {
xmlHttp = new XMLHttpRequest();
}
return xmlHttp;
}
var xmlReq = createXMLHTTP();
// 发送ajax处理请求(这里简单验证用户名和密码的有效性，默认正确的输入：用户名和密码都是test)
function validatePwd(oTxt) {
var url = "/AjaxOperations.aspx";
xmlReq.open("post", url, true);
xmlReq.setRequestHeader("Content-Length", oTxt.value.length + $("txtUserName").value.length);
xmlReq.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
xmlReq.onreadystatechange = callBack;
xmlReq.send("action=chkPwd&userInfos=" + escape(oTxt.value + "/" + $("txtUserName").value)); // 发送文本
}
function callBack() {
if (xmlReq.readyState == 4) {
if (xmlReq.status == 200) {
alert(xmlReq.responseText); // 接收文本
}
else if (xmlReq.status == 404) {
alert("Requested URL is not found.");
} else if (xmlReq.status == 403) {
alert("Access denied.");
} else
alert("status is " + xmlReq.status);
}
}
Code//jsTest.htm
<html>
<head>
<title>js test</title>
<script src="js/testJs.js" type="text/javascript"></script>
</head>
<body>
<form id="form1">
<div>
用户名：<input id="txtUserName" name="txtUserName" type="text" /> 密码：<input id="txtPwd" name="txtPwd" type="password" onblur="validatePwd(this)" /></div>
</form>
</body>
</html>
//AjaxOperations.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="AjaxOperations.aspx.cs" Inherits="WebTest2008.AjaxOperations" %>
// AjaxOperations.aspx.cs
using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace WebTest2008
{
public partial class AjaxOperations : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!string.IsNullOrEmpty(Request["action"]) && Request["action"] == "chkPwd")
{
string responseTxt = "用户名和密码不匹配！";
string tempStr = Request["userInfos"];
/* 测试用 实际项目中可以对数据库进行检索等等相关操作，这里简化了 */
if (tempStr.Split(new char[] { \'/\' }, StringSplitOptions.RemoveEmptyEntries)[0] == "test" && tempStr.Split(new char[] { \'/\' }, StringSplitOptions.RemoveEmptyEntries)[1] == "test")
{
responseTxt = "验证通过！";
}
Response.Write(responseTxt);
}
}
}
}
上面这种方式是最简单最直接也是最有效的方式。熟练使用最佳。
二、XML方式
1、发送XML数据
Code//testJs.js
// 此函数等价于document.getElementById /document.all
function $(s) { if (document.getElementById) { return eval(\'document.getElementById("\' + s + \'")\'); } else { return eval(\'document.all.\' + s); } }
// 创建 XMLHttpRequest对象，以发送ajax请求
function createXMLHTTP() {
var xmlHttp = false;
var arrSignatures = ["MSXML2.XMLHTTP.5.0", "MSXML2.XMLHTTP.4.0",
"MSXML2.XMLHTTP.3.0", "MSXML2.XMLHTTP",
"Microsoft.XMLHTTP"];
for (var i = 0; i < arrSignatures.length; i++) {
try {
xmlHttp = new ActiveXObject(arrSignatures[i]);
return xmlHttp;
}
catch (oError) {
xmlHttp = false; //ignore
}
}
// throw new Error("MSXML is not installed on your system.");
if (!xmlHttp && typeof XMLHttpRequest != \'undefined\') {
xmlHttp = new XMLHttpRequest();
}
return xmlHttp;
}
var xmlReq = createXMLHTTP();
// 发送ajax处理请求(这里简单验证用户名和密码的有效性，默认正确的输入：用户名和密码都是test)
function validatePwd(oTxt) {
var url = "/AjaxOperations.aspx?action=xmlOp";
var xmlStr = "<profile>" +
" <userName>" + escape($("txtUserName").value) + "</userName>" +
" <userPwd>" + escape($("txtPwd").value) + "</userPwd>" +
"</profile>";
xmlReq.open("post", url, true);
// Tell the server you\'re sending it XML
xmlReq.setRequestHeader("Content-Type", "text/xml"); // 这里注意
xmlReq.onreadystatechange = callBack;
xmlReq.send(xmlStr); // 发送XML
}
function callBack() {
if (xmlReq.readyState == 4) {
if (xmlReq.status == 200) {
alert(xmlReq.responseText); // 接收文本
}
else if (xmlReq.status == 404) {
alert("Requested URL is not found.");
} else if (xmlReq.status == 403) {
alert("Access denied.");
} else
alert("status is " + xmlReq.status);
}
}
Code// AjaxOperations.aspx.cs
using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Xml;
namespace WebTest2008
{
public partial class AjaxOperations : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!string.IsNullOrEmpty(Request["action"]) && Request["action"] == "xmlOp") // 处理xml
{
XmlDocument doc = new XmlDocument();
try
{
doc.Load(Request.InputStream); //获取xml数据(这里需要注意接受xml数据的方法)
}
catch (Exception ex)
{
throw ex;
}
string responseTxt = "";
string tempName = doc.SelectSingleNode("profile/userName").InnerText;
string tempPwd = doc.SelectSingleNode("profile/userPwd").InnerText;
if (tempName == "test" && tempPwd == "test")
{
responseTxt = "验证通过！";
}
else responseTxt = "验证失败！";
Response.Write(responseTxt); // 写文本
}
}
}
}
2、接收XML数据：
我们看到，上面两个.js文件里处理返回数据时都用到了xmlReq.responseText的属性，下面我们试试看xmlReq.responseXML属性：
Code//testJs.js
// 此函数等价于document.getElementById /document.all
function $(s) { if (document.getElementById) { return eval(\'document.getElementById("\' + s + \'")\'); } else { return eval(\'document.all.\' + s); } }
// 创建 XMLHttpRequest对象，以发送ajax请求
function createXMLHTTP() {
var xmlHttp = false;
var arrSignatures = ["MSXML2.XMLHTTP.5.0", "MSXML2.XMLHTTP.4.0",
"MSXML2.XMLHTTP.3.0", "MSXML2.XMLHTTP",
"Microsoft.XMLHTTP"];
for (var i = 0; i < arrSignatures.length; i++) {
try {
xmlHttp = new ActiveXObject(arrSignatures[i]);
return xmlHttp;
}
catch (oError) {
xmlHttp = false; //ignore
}
}
// throw new Error("MSXML is not installed on your system.");
if (!xmlHttp && typeof XMLHttpRequest != \'undefined\') {
xmlHttp = new XMLHttpRequest();
}
return xmlHttp;
}
var xmlReq = createXMLHTTP();
// 发送ajax处理请求(这里简单验证用户名和密码的有效性，默认正确的输入：用户名和密码都是test)
function validatePwd(oTxt) {
var url = "/AjaxOperations.aspx?action=xmlOp";
var xmlStr = "<profile>" +
" <userName>" + escape($("txtUserName").value) + "</userName>" +
" <userPwd>" + escape($("txtPwd").value) + "</userPwd>" +
"</profile>";
xmlReq.open("post", url, true);
// Tell the server you\'re sending it XML
xmlReq.setRequestHeader("Content-Type", "text/xml");
xmlReq.onreadystatechange = callBack;
xmlReq.send(xmlStr); // 发送XML
}
function callBack() {
if (xmlReq.readyState == 4) {
if (xmlReq.status == 200) {
var xmlDoc = xmlReq.responseXML; // 接收XML
// var nodes = xmlDoc.childNodes;
// alert("文件根标签的名称： " + xmlDoc.documentElement.tagName);
// alert("根元素共有子节点个数: " + xmlDoc.documentElement.childNodes.length);
alert(xmlDoc.documentElement.childNodes(0).text);
}
else if (xmlReq.status == 404) {
alert("Requested URL is not found.");
} else if (xmlReq.status == 403) {
alert("Access denied.");
} else
alert("status is " + xmlReq.status);
}
}
Codeusing System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Xml;
namespace WebTest2008
{
public partial class AjaxOperations : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!string.IsNullOrEmpty(Request["action"]) && Request["action"] == "xmlOp") // 处理xml
{
XmlDocument doc = new XmlDocument();
try
{
doc.Load(Request.InputStream); //获取xml数据
}
catch (Exception ex)
{
throw ex;
}
string responseXmlTxt = "";
string tempName = doc.SelectSingleNode("profile/userName").InnerText;
string tempPwd = doc.SelectSingleNode("profile/userPwd").InnerText;
if (tempName == "test" && tempPwd == "test")
{
responseXmlTxt = "<?xml version=\"1.0\" encoding=\"utf-8\" ?> <msg>验证通过！</msg>"; // 测试用，简单的xml文件
}
else responseXmlTxt = "<?xml version=\"1.0\" encoding=\"utf-8\" ?><msg>验证失败！</msg>";
Response.ContentType = ("text/xml;charset=UTF-8"); // 这里必须要设置，否则客户端接收不到这里写好的xml文件
Response.Write(responseXmlTxt); // 写xml
Response.End();
}
}
}
}
好了，前面两种方法是大家平时开发中比较熟悉的方式，下面我们来看看第三种方式。
三、JSON方式
json的准备知识：
json是一种简单的数据格式，比xml更轻巧。json是JavaScript 的原生格式，这意味着在 JavaScript 中处理json格式的 数据不需要任何特殊的API 或工具包。json的语法规则其实很简单：对象是一个无序的“‘名称/值’对”集合。一个对象以“{”（左括号）开始，“}”（右括号）结束。每个“名称”后跟一个“:”（冒号）；“‘名称/值’ 对”之间使用“,”（逗号）分隔。看个例子先：
Codefunction testJson() {
//定义一个user(json的格式,其实就是定义一个js函数(变量)的方式而已)
var user =
{
"username": "jeff wong",
"age": 25,
"info": { "tel": "12345678", "cellphone": "13312345678" },
"address": // 数组
[
{ "city": "beijing", "postcode": "101110" },
{ "city": "ny city", "postcode": "911119" }
]
}
alert(user.username);
alert(user.age);
alert(user.info.cellphone);
alert(user.address[0].city);
alert(user.address[0].postcode);
user.username = "xiao wang";
alert(user.username);
}
上面的定义方式看起来很简单，但是如果字段众多，命名方式混杂，出错的概率大大增加，怎么办？这时候你就会想到用程序的方式生成json数据。json提供了json.js包，专门提供了几种常用的json处理函数。下载下来， ，将其引入然后就可以简单的使用object.toJSONString()转换成json数据。看代码：
Codefunction Car(maker, model, year, color) {
this.maker = maker;
this.model = model;
this.year = year;
this.color = color;
}
function testJson() {
var tempCar = new Car("VW", "S", 1999, "yellow");
alert(tempCar.toJSONString());
}
Codefunction testJson() {
var str = \'{ "name": "jeff wong", "age": 25,"address":"beijing"}\';
var tempObj = eval(\'(\' + str + \')\');
alert(tempObj.toJSONString()); //使用eval方法
var tempObj1 = str.parseJSON();
alert(tempObj1.toJSONString()); // 或者使用parseJSON()方法
}
ajax利用json发送/接收数据：
Code// 此函数等价于document.getElementById /document.all
function $(s) { if (document.getElementById) { return eval(\'document.getElementById("\' + s + \'")\'); } else { return eval(\'document.all.\' + s); } }
// 创建 XMLHttpRequest对象，以发送ajax请求
function createXMLHTTP() {
var xmlHttp = false;
var arrSignatures = ["MSXML2.XMLHTTP.5.0", "MSXML2.XMLHTTP.4.0",
"MSXML2.XMLHTTP.3.0", "MSXML2.XMLHTTP",
"Microsoft.XMLHTTP"];
for (var i = 0; i < arrSignatures.length; i++) {
try {
xmlHttp = new ActiveXObject(arrSignatures[i]);
return xmlHttp;
}
catch (oError) {
xmlHttp = false; //ignore
}
}
// throw new Error("MSXML is not installed on your system.");
if (!xmlHttp && typeof XMLHttpRequest != \'undefined\') {
xmlHttp = new XMLHttpRequest();
}
return xmlHttp;
}
var xmlReq = createXMLHTTP();
// 发送ajax处理请求(这里简单验证用户名和密码的有效性，默认正确的输入：用户名和密码都是test)
function validatePwd(oTxt) {
var url = "/AjaxOperations.aspx?action=jsonOp";
// JSON就只是文本,由于不需要特殊编码而且每个服务器端脚本都能处理文本数据，所以可以轻松利用JSON并将其应用到服务器。
var str = \'{ "userName":"\' + $("txtUserName").value + \'", "userPwd": "\' + $("txtPwd").value + \'"}\';
var jsonStr = str.parseJSON().toJSONString(); // you\'re sending it JSON
xmlReq.open("post", url, true);
xmlReq.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
xmlReq.onreadystatechange = callBack;
xmlReq.send("sendStr=" + jsonStr); // 发送JSON(在服务器上解释JSON)
}
function callBack() {
if (xmlReq.readyState == 4) {
if (xmlReq.status == 200) {
var jsonStr = xmlReq.responseText.parseJSON().toJSONString(); //转化为json数据
alert(jsonStr);
}
else if (xmlReq.status == 404) {
alert("Requested URL is not found.");
} else if (xmlReq.status == 403) {
alert("Access denied.");
} else
alert("status is " + xmlReq.status);
}
}
Codeusing System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace WebTest2008
{
public partial class AjaxOperations : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!string.IsNullOrEmpty(Request["action"]) && Request["action"] == "jsonOp") // 处理JSON
{
string responseJsonTxt = "";
string tempStr = Request["sendStr"].Trim(new char[] { \'{\', \'}\' }); // 在服务器上解释JSON需要引用一个能够转化JSON的组件:Json.Net,这里简单测试，略过Json.Net
if (tempStr.Split(new char[] { \',\' })[0].Split(new char[] { \':\' })[1] == "\"test\"" && tempStr.Split(new char[] { \',\' })[1].Split(new char[] { \':\' })[1] == "\"test\"")
{
responseJsonTxt = "{\"msg\":\"验证通过！\"}"; // 测试用
}
else responseJsonTxt = "{\"msg\":\"验证失败！\"}";
Response.Write(responseJsonTxt);
Response.End();
}
}
Code<html>
<head>
<title>js test</title>
<script src="js/json.js" type="text/javascript"></script>
<script src="js/testJs.js" type="text/javascript"></script>
</head>
<body>
<form id="form1">
<div>
用户名：<input id="txtUserName" name="txtUserName" type="text" />
密码：<input id="txtPwd" name="txtPwd" type="password" onblur="validatePwd(this)" /></div>
</form>
</body>
</html>