关于UTF-8的客户端用AJAX方式获取GB2312的服务器端乱码问题的解决办法

客户端是UTF-8编码，这也是现在大家公认的标准编码
在这种情况下，实用AJAX异步获取GB2312编码的服务器端信息时，不可避免的要遇到汉字乱码问题
因为目标数据是GB2312，但XMLHttpRequest默认是用UTF-8来进行数据封装的，因此会产生乱码
相信很多人都在用轻量级的JS工具集-prototype.js，它的AJAX功能同样很出色
我也一直在用它，因此对于这个问题也一直是基于 prototype.js来考虑的
但经过多次试验，还是没能把它返回的 responseText 转成正确的编码格式
后来了解到，在XMLHttpRequest对象的 responseBody 属性中，保存了原始的数据信息
但prototype.js的AJAX功能返回的 responseBody 属性是 undefined，看来还是要自己动手了
经过近一个小时的敲打，一个短小精悍的AJAX框架腾空出世了，哈哈，不过功能还是很全的
里面某些写法借鉴了另一个轻量级的AJAX框架-bingo.js的实现方式
调用方式及注释：

myAjaxCall({ 
url : 'xxxxx.jsp' //目标页面地址 
,params : URLEncoding('prm1=参数1&prm2=参数2') //参数串信息 
,method : 'POST' //发送方式POST or GET 
,callBack : retValue //回调函数名称 
,isBody : true //是否返回 responseBody ，默认返回 responseText 
//,isXml : false //是否以XML格式返回数据 
//,errorReport : false //发送错误时，是否弹出提示 
//,attachs : {} //附加的其他参数，可传递给回调函数 
}); 
function retValue(res,att){ 
var strRet = bytes2BSTR(res); 
alert(strRet); 
}

注意看其中的两个函数：

、URLEncoding ：对参数进行编码
、bytes2BSTR ：对返回的数据进行解码

这两个函数直接借鉴了网络上很流行的两个编码函数，不过都是用vbs写的
需要把这两个函数也附加到上面的页面里：

Function URLEncoding(vstrIn) 
strReturn = "" 
For i = 1 To Len(vstrIn) 
ThisChr = Mid(vStrIn,i,1) 
If Abs(Asc(ThisChr)) < &HFF Then 
strReturn = strReturn & ThisChr 
Else 
innerCode = Asc(ThisChr) 
If innerCode < 0 Then 
innerCode = innerCode + &H10000 
End If 
Hight8 = (innerCode And &HFF00) \ &HFF 
Low8 = innerCode And &HFF 
strReturn = strReturn & "%" & Hex(Hight8) & "%" & Hex(Low8) 
End If 
Next 
URLEncoding = strReturn 
End Function 
Function bytes2BSTR(vIn) 
strReturn = "" 
For i = 1 To LenB(vIn) 
ThisCharCode = AscB(MidB(vIn,i,1)) 
If ThisCharCode < &H80 Then 
strReturn = strReturn & Chr(ThisCharCode) 
Else 
NextCharCode = AscB(MidB(vIn,i+1,1)) 
strReturn = strReturn & Chr(CLng(ThisCharCode) * &H100 + CInt(NextCharCode)) 
i = i + 1 
End If 
Next 
bytes2BSTR = strReturn 
End Function

下面附上我写的轻量级Ajax框架 - myAjax.js 源码：

/** 
2 * myAjax 
3 * by netwild 
4 * [e-mail] 
5 */ 
6 var myAjaxConfig = { 
7 "url":"" 
8 ,"params":"" 
9 ,"method":"GET" 
,"callBack":function(){} 
,"isXml":false 
,"isBody":false 
,"isCache":false 
,"errorReport":true 
,"statePoll":null 
,"postData":null 
,"attachs":{} 
}; 
function myAjaxCall(requestJson){ 
var attach; 
if(requestJson && typeof requestJson == "object"){ 
if(requestJson.url){myAjaxConfig.url = requestJson.url;} 
if(requestJson.params){myAjaxConfig.params = requestJson.params;} 
if(requestJson.method){myAjaxConfig.method = requestJson.method;} 
if(requestJson.callBack){myAjaxConfig.callBack = requestJson.callBack;} 
if(requestJson.isXml){myAjaxConfig.isXml = requestJson.isXml;} 
if(requestJson.isBody){myAjaxConfig.isBody = requestJson.isBody;} 
if(requestJson.isCache){myAjaxConfig.isCache = requestJson.isCache;} 
if(requestJson.statePoll){myAjaxConfig.statePoll = requestJson.statePoll;} 
if(requestJson.attachs){myAjaxConfig.attachs = requestJson.attachs;} 
} 
if(!myAjaxConfig.isCache){ 
var nocache = new Date().getTime(); 
if(myAjaxConfig.url.indexOf("?")>0){myAjaxConfig.url += "&nocache=" + nocache;} 
else{myAjaxConfig.url += "?nocache=" + nocache;} 
} 
var newCall = new myAjaxCore(); 
newCall.init(); 
} 
function myAjaxCore(){ 
var _self = this; 
var _state,_status; 
var _httpRequest,_attach; 
//////////////////////////////////////////////////// 
this.init = function(){ 
if (window.XMLHttpRequest){ 
_httpRequest = new XMLHttpRequest(); 
if (_httpRequest.overrideMimeType) { 
_httpRequest.overrideMimeType('text/xml'); 
} 
}else if (window.ActiveXObject) { 
var MSXML = ['MSXML2.XMLHTTP.6.0','MSXML2.XMLHTTP.3.0','MSXML2.XMLHTTP.5.0','MSXML2.XMLHTTP.4.0','MSXML2.XMLHTTP', 'Microsoft.XMLHTTP']; 
for(var n=0;n<MSXML.length;n++){ 
try { 
_httpRequest = new ActiveXObject(MSXML[n]); 
break; 
}catch(e){} 
} 
} 
with(_httpRequest) { 
onreadystatechange = _self.getResponse; 
open(myAjaxConfig.method,myAjaxConfig.url,true); 
if(myAjaxConfig.method == "POST" && (myAjaxConfig.params != "")){ 
setRequestHeader("Content-Length",myAjaxConfig.params.length); 
setRequestHeader("Content-Type","application/x-www-form-urlencoded"); 
send(myAjaxConfig.params); 
}else{ 
var textType = myAjaxConfig.isXml?"text/xml":"text/plain"; 
_httpRequest.setRequestHeader('Content-Type',textType); 
if(browser.IE){ 
setRequestHeader("Accept-Encoding", "gzip, deflate"); 
}else if(browser.FF){ 
setRequestHeader("Connection","close"); 
} 
send(null); 
} 
} 
}; 
//////////////////////////////////////////////////// 
this.getResponse = function(){ 
_state = _httpRequest.readyState; 
if(_httpRequest.readyState == 4 && _httpRequest.status){_status = _httpRequest.status;} 
if(myAjaxConfig.statePoll){myAjaxConfig.statePoll(_httpRequest.readyState);} 
if(_httpRequest.readyState==4 && _httpRequest.status>=400){ 
_self.abort(); 
_self.alertf("ERROR:HTTP response code "+_httpRequest.status); 
} 
if(_httpRequest.readyState==4 && _httpRequest.status==200){ 
var response_content; 
if(myAjaxConfig.isXML){ 
response_content = _httpRequest.responseXML; 
}else if(myAjaxConfig.isBody){ 
response_content = _httpRequest.responseBody; 
}else{ 
response_content = _httpRequest.responseText; 
} 
if(typeof myAjaxConfig.callBack == "function"){ 
myAjaxConfig.callBack(response_content,myAjaxConfig.attachs); 
}else{ 
eval(myAjaxConfig.callBack+"(response_content,myAjaxConfig.attachs)"); 
} 
} 
}; 
//////////////////////////////////////////////////// 
this.abort=function(){_httpRequest.abort();}; 
this.state=function(){return _state;}; 
this.status=function(){return _status;}; 
this.destory=function(){_self.abort();delete(_httpRequest);}; 
this.alertf=function(error){if(myAjaxConfig.errorReport){alert(error);}}; 
} 
if(!browser){ 
var browser={}; 
browser.IE = browser.ie = window.navigator.userAgent.indexOf("MSIE")>0; 
browser.Firefox = browser.firefox = browser.FF = browser.MF = navigator.userAgent.indexOf("Firefox")>0; 
browser.Gecko = browser.gecko = navigator.userAgent.indexOf("Gecko")>0; 
browser.Safari = browser.safari=navigator.userAgent.indexOf("Safari")>0; 
browser.Camino = browser.camino=navigator.userAgent.indexOf("Camino")>0; 
browser.Opera = browser.opera=navigator.userAgent.indexOf("Opera")>0; 
browser.other = browser.OT=!(browser.IE || browser.FF || browser.Safari || browser.Camino || browser.Opera); 
}