JavaScriptAjax类实例代码

/*
 AJAX v1.4
 HJF 2009-7-5
*/
function AjaxDO(){ this.HttpRequest = null;
 this.openMethod = null; //HTTP请求的方法，为Get、Post 或者Head
 this.openURL = null; //是目标URL。基于安全考虑，这个URL 只能是同网域的，否则会提示“没有权限”的错误。
 this.openAsync = null; //是指定在等待服务器返回信息的时间内是否继续执行下面的代码。如果为False，则不会继续执行，直到服务器返回信息。默认为True。
 this.ProcessRequestFunction = function(_HttpRequest) {return;} //处理返回信息的函数入口
 this.ProcessRequestParam = null; //处理访问信息时的附加参数
 this.LoadingImg = null; //正在载入的图片，一般为.gif动画
 //初始化HttpRequest
 this.InitHttpRequest = function(){
 var http;
 // try {
 // http = new ActiveXObject("Msxml2.XMLHTTP");
 // } catch(e) {
 // try {
 // http = new ActiveXObject("Microsoft.XMLHTTP");
 // } catch(e) {
 // http = false;
 // }
 // }
 try {
 if(window.ActiveXObject){
 for(var i=5; i; i--){
 try{
 if(i==2){
 http = new ActiveXObject("Microsoft.XMLHTTP");
 }else{
 http = new ActiveXObject( "Msxml2.XMLHTTP." + i + ".0" );
 }
 break;
 }catch(e){
 //alert(i);
 http = false;
 }
 }
 }else if(window.XMLHttpRequest){
 http = new XMLHttpRequest();
 if(http.overrideMimeType){
 http.overrideMimeType("text/xml");
 }
 }
 }catch(e){
 http = false;
 }
 if(!http){
 Alert("不能创建XMLHttpRequest对象实例");
 return http;
 }
 this.HttpRequest = http;
 return http;
 }
 //检测 this.HttpRequest
 this.checkHttpRequest = function(){
 if(!this.HttpRequest){
 return this.InitHttpRequest();
 }
 return this.HttpRequest;
 }
 //修改MIME类别
 //http.setRequestHeader("Content-Type", "application/x-www-form-urlencoded"); //如果要传文件或者Post 内容给服务器
 //http.setRequestHeader("Content-Type","text/xml");
 //http.setRequestHeader("Content-Type","gb2312");
 this.setRequestHeader = function(mime){
 if(!this.checkHttpRequest()){
 return false;
 }
 try{
 this.HttpRequest.setRequestHeader("Content-Type", mime);
 return true;
 }catch(e){
 if(e instanceof Error){
 Alert("修改MIME类别错误");
 return false;
 }
 }
 }
 //设置状态改变的事件触发器
 this.setOnReadyStateChange = function(funHandle, Param){
 if(!this.checkHttpRequest()){
 return false;
 }
 this.ProcessRequestFunction = funHandle;
 this.ProcessRequestParam = Param;
 return true;
 }
 this.setLoadingImg = function(ImgID){
 this.LoadingImg = ImgID;
 }
 //建立HTTP连接
 //open("method","URL"[,asyncFlag[,"userName"[, "password"]]])
 this.Open = function(method, url, async, username, psw){
 if(!this.checkHttpRequest()){
 return false;
 }
 this.openMethod = method;
 this.openURL = url;
 this.openAsync = async;
 if((this.openMethod==null) || ((this.openMethod.toUpperCase()!="GET")&&(this.openMethod.toUpperCase()!="POST")&&(this.openMethod.toUpperCase()!="HEAD"))){
 Alert("请指定HTTP请求的方法，为Get、Post 或者Head");
 return false;
 }
 if((this.openURL==null)||(this.openURL=="")){
 Alert("请指定目标URL");
 return false;
 }
 try{
 this.HttpRequest.open(this.openMethod, this.openURL, this.openAsync, username, psw);
 }catch(e){
 if(e instanceof Error){
 Alert("无法建立HTTP连接");
 return false;
 }
 }
 if(this.openMethod.toUpperCase()=="POST"){
 if(!this.setRequestHeader("application/x-www-form-urlencoded")){
 Alert("修改MIME类别失败");
 return false;
 }
 }
 if(this.openAsync){ //异步模式，程序继续执行
 if(this.ProcessRequestFunction==null){
 Alert("请指定处理返回信息的函数");
 return false;
 }
 var _http_request_ajax = this.HttpRequest;
 var _this_ajax = this;
 this.HttpRequest.onreadystatechange = function(){
 if(_http_request_ajax.readyState==4) {
 if(_http_request_ajax.status==200) {
 _this_ajax.ProcessRequestFunction(_http_request_ajax, _this_ajax.ProcessRequestParam, _this_ajax.LoadingImg);
 }else{
 Alert("您所请求的页面有异常。");
 return false;
 }
 }
 }
 }
 if(this.LoadingImg!=null){
 funShow(this.LoadingImg);
 }
 return true;
 }
 //向服务器发出HTTP请求
 //格式：name=value&anothername=othervalue&so=on
 this.Send = function(idata){
 if(!this.checkHttpRequest()){
 return false;
 }
 var data = null;
 if(this.openMethod.toUpperCase()=="POST"){
 data = funEscapeAll(idata);
 }
 try{
 this.HttpRequest.send(data);
 return true;
 }catch(e){
 if(e instanceof Error){
 Alert("向服务器发出HTTP请求失败");
 return false;
 }
 }
 }
 //处理服务器返回的信息
 this.getResponseText = function(type){
 if(!this.checkHttpRequest()){
 return false;
 }
 if(this.HttpRequest.readyState==4) {
 if(this.HttpRequest.status==200) {
 if((type!=null) && (type.toUpperCase()=="XML")){
 return this.HttpRequest.responseXML;
 }
 return this.HttpRequest.responseText;
 }else{
 Alert("您所请求的页面有异常。");
 return false;
 }
 }
 }
 //停止当前请求
 this.abort = function(){
 if(!this.checkHttpRequest()){
 return false;
 }
 if(this.LoadingImg!=null){
 funHide(this.LoadingImg);
 }
 if(this.HttpRequest.readyState>0 && this.HttpRequest.readyState<4){
 this.HttpRequest.abort();
 }
 }
}
//=====================================================================================
//公共函数
//=====================================================================================
function $(_obj){
 var o;
 if (typeof(_obj)!="string")
 return _obj;
 else{
 try{
 document.all;
 try{
 o=document.all(_obj);
 }catch(e){
 return null;
 }
 }catch(ee){
 try{
 o=document.getElementById(_obj);
 }catch(e){
 return null;
 }
 }
 return o;
 }
}
function funEscapeAll(str){
 var t = "&";
 var s = str.split(t);
 if(s.length<=0) return str;
 for(var i=0; i<s.length; i++){
 s[i] = funEscapeOne(s[i]);
 }
 return s.join(t);
}
function funEscapeOne(str){
 var i = str.indexOf("=");
 if(i==-1) return str;
 var t = URLEncode(str.substr(i+1));
 return str.substring(0, i+1)+t;
}
function URLEncode(str){
 return encodeURIComponent(str);
/* 
 return escape(str).replace(/\+/g, "%2B").
 replace(/\"/g,"%22").
replace(/\'/g, "%27").
replace(/\//g,"%2F");
*/
}
function funEscapeXML(content) {
if (content == undefined)
return "";
if (!content.length || !content.charAt)
content = new String(content);
var result = "";
var length = content.length;
for (var i = 0; i < length; i++) {
var ch = content.charAt(i);
switch (ch) {
case '&':
result += "&";
break;
case '<':
result += "<";
break;
case '>':
result += ">";
break;
case '"':
result += """;
break;
case '\'':
result += "'";
break;
default:
result += ch;
}
}
return result;
}
function funShow(_obj){
 if(typeof(_obj)=="object")
 _obj.style.visibility = "inherit";
 else
 $(_obj).style.visibility = "inherit";
}
function funHide(_obj){
 if(typeof(_obj)=="object")
 _obj.style.visibility = "hidden";
 else
 $(_obj).style.visibility = "hidden";
}
function Alert(str){
 alert(str);
 //window.status = str;
}
/*
使用例子：
function processRequest(http_request, _val, _loading_img){
 if(http_request.responseXML.documentElement){
 //alert(decodeURIComponent(http_request.responseXML.documentElement.xml));
 }else{
 //alert(decodeURIComponent(http_request.responseText));
 }
 alert(_val);
 funHide(_loading_img);
}
1、GET
 var ajax = new AjaxDO();
 ajax.setLoadingImg(_loading_img);
 ajax.setOnReadyStateChange(processRequest, _val);
 ajax.Open("GET", url, true); //异步模式，程序继续执行
 ajax.Send("");
 ajax.Open("GET", url, false); //非异步模式，程序等待
 ajax.Send("");
 var xml_doc = ajax.getResponseText("XML");
 var text_doc = ajax.getResponseText("TEXT");
2、POST
 var ajax = new AjaxDO();
 ajax.setLoadingImg(_loading_img);
 ajax.setOnReadyStateChange(processRequest, _val);
 ajax.Open("POST", url, true); //异步模式，程序继续执行
 ajax.Send(data);
 ajax.Open("POST", url, false); //非异步模式，程序等待
 ajax.Send(data);
 var xml_doc = ajax.getResponseText("XML");
 var text_doc = ajax.getResponseText("TEXT");
 
注，客户端发送带有中文或HTML脚本的信息时，发送的信息必须调用：encodeURIComponent函数，例如：
var data = encodeURIComponent($('message').value);
实际是调用了两次，Ajax类内部又调用一次。
服务端（Java版）需要做下转码：
String message = request.getParameter("message");
message = URLDecoder.decode(message, "UTF-8");
*/
注，客户端发送带有中文或HTML脚本的信息时，发送的信息必须调用：encodeURIComponent函数，例如：
String message = request.getParameter("message");
message = URLDecoder.decode(message, "UTF-8");
2、Demo.html
Ajax类<style type="text/css"><!--
#Layer1 {
 position:absolute;
 left:670px;
 top:11px;
 width:15px;
 height:15px;
 z-index:10000;
 background-color:#FF0000;
 font-size:13;
 border:none;
 visibility:hidden;
}
--></style><style type="text/css" bogus="1">#Layer1 {
 position:absolute;
 left:670px;
 top:11px;
 width:15px;
 height:15px;
 z-index:10000;
 background-color:#FF0000;
 font-size:13;
 border:none;
 visibility:hidden;
}</style>
</head>
<body>
<div id="Layer1"><img src="http://www.gxlcms.com/article/indicator_flower.gif" src="http://www.gxlcms.com/article/indicator_flower.gif" /></div>
<script type="text/javascript" language="javascript"><!--
function processRequest(http_request, _val, _loading_img){
 alert(http_request.responseXML.documentElement.xml);
 //alert(http_request.responseText);
 funHide(_loading_img);
}
// --></script>
<script type="text/javascript" language="javascript"><!--
var url = "http://www.w3schools.com/xml/simple.xml";
var data = "";
var ajax = new AjaxDO();
function btnAjax1(){
 //var ajax = new AjaxDO();
 //ajax.InitHttpRequest();
 ajax.abort();
 ajax.setLoadingImg(document.getElementById("Layer1"));
 ajax.setOnReadyStateChange(processRequest);
 ajax.Open("GET", url, true); //异步模式，程序继续执行
 ajax.Send("");
}
function btnAjax2(){
 //var ajax = new AjaxDO();
 //ajax.InitHttpRequest();
 ajax.abort();
 ajax.Open("GET", url, false); //非异步模式，程序等待
 ajax.Send("");
 alert(ajax.getResponseText("XML").documentElement.xml);
 alert(ajax.getResponseText("TEXT"));
}
// --></script>
<button >异步模式</button>
<button >非异步模式</button>
</body>
</html>