javascript Ajax 类实现代码


            与现在那些Ajax框架比较，优劣之处？看完再说吧： 1、Ajax.js 复制代码 代码如下:/*     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： 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"); 2、Demo.html复制代码 代码如下:<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=gb2312" /> <title>Ajax类</title> <script src="Ajax.js" src="Ajax.js"></script> <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="indicator_flower.gif" src="indicator_flower.gif" width="15" /></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 onclick="btnAjax1()">异步模式</button> <button onclick="btnAjax2()">非异步模式</button> </body> </html>

3、图片