Ajax跨域代理访问网络资源的实现代码

<script language="jscript" runat="server"> 
/* 
在VBS里面的调用方法 
dim myhttp 
set myhttp = SmartHttp(url,method,data); //三个参数均可选 
属性： 
url：String，请求的URL地址 
method：String，请求的方法 
data：String，请求的数据 
charset：String，请求的URL返回数据的编码 
status：Int，请求返回的状态码 
readyState：Int，同HTTP请求的当前通讯状态，1、2、3、4 
dataset：Object，请求的数据，如果增加了，会将这部分数据附加到data属性 
dataset属性： 
charset：String，发送数据的编码 
dataset方法： 
append(key,value,noencode)：添加数据 
remove(key)：移除某个数据项 
isexists(key)：判断某个数据项是不是存在 
clear：清除所有数据项 
方法： 
header(headstr)：设置请求头，项和值之间用:分开 
timeout(t1,t2,t3,t4)：设置超时时间 
send()：发送请求 
getbinary：获取服务器返回的二进制数据 
gettext(charset)：获取指定编码的文本 
getjson(charset)：获取指定编码的json数据 
getheader(key)：获取服务器返回的响应头 
getxml(charset)：获取指定编码的xml数据 
*/ 
function SmartHttp(url,method,data){ 
return new _SmartHttp(url,method,data); 
} 

function _SmartHttp(url,method,data){ 
if(typeof method=="undefined") method="GET"; 
if(typeof data=="undefined") data=""; 
method = method.toUpperCase(); 
method = method!="POST" ? "GET" : "POST"; 
this.timeout=[10000,10000,10000,10000]; 
this.method = method; 
this.url=url; 
this.data=data; 
this.charset="gb2312"; 
this.http=null; 
this.headers=[]; 
this.status=0; 
this.readyState=0; 
this.content=null; 
this.msg=""; 
this.dataset={ 
charset:"gb2312", 
data:[], 
append:function(key,value,noencode){ 
var fn=null; 
if(this.charset.toLowerCase()=="utf-8"){fn = encodeURIComponent;}else{fn = escape;} 
if(noencode==true){fn=function(_str){return _str;}} 
this.data.push({"key":fn(key),"value":fn(value)}); 
}, 
remove:function(key){ 
if(this.data.length<=0) return false; 
var _data=[]; 
for(var i=0;i<this.data.length;i++){ 
if(this.data[i].key!=key){ 
_data.push(this.data[i]); 
} 
} 
this.data = _data; 
}, 
isexists:function(key){ 
if(this.data.length<=0) return false; 
for(var i=0;i<this.data.length;i++){ 
if(this.data[i].key==key){ 
return true; 
} 
} 
return false; 
}, 
clear:function(){ 
this.dataset.data=[]; 
} 
}; 
} 

_SmartHttp.prototype.init=function(){ 
var datasetstr=""; 
if(this.dataset.data.length>0){ 
for(var i=0;i<this.dataset.data.length;i++){ 
datasetstr += this.dataset.data[i].key + "=" + this.dataset.data[i].value + "&"; 
} 
} 
if(datasetstr!="") datasetstr = datasetstr.substr(0,datasetstr.length-1); 
if(this.data==""){this.data = datasetstr;}else{if(datasetstr!="")this.data+= "&" + datasetstr;} 
if(this.data=="")this.data=null; 
//this.url += ((this.url.indexOf("?")<0) ? "?" : "&") + "jornd=" + this.getrnd(); 
if(this.method=="GET" && this.data!=null) this.url += "&" + this.data; 
if(this.method=="POST") this.headers.push("Content-Type:application/x-www-form-urlencoded"); 
if(!this.charset || this.charset=="") this.charset = "gb2312"; 
}; 

_SmartHttp.prototype.header=function(headstr){ 
if(headstr.indexOf(":")>=0) this.headers.push(headstr); 
return this; 
}; 

_SmartHttp.prototype.timeout=function(){ 
if(arguments.length>4){return this;} 
for(var i =0;i<arguments.length;i++){ 
if(!isNaN(arguments[i])){ 
this.timeout[i] = parseInt(arguments[i]); 
} 
} 
return this; 
}; 

_SmartHttp.prototype.send=function(){ 
this.init(); 
var _http = this.getobj(); 
if(_http==null){return this;} 
try{ 
_http.setTimeouts(this.timeout[0], this.timeout[1], this.timeout[2], this.timeout[3]); 
}catch(ex){} 
_http.open(this.method,this.url,false); 
if(this.headers.length>0){ 
for(var i=0;i<this.headers.length;i++){ 
var Sindex = this.headers[i].indexOf(":"); 
var key = this.headers[i].substr(0,Sindex); 
var value = this.headers[i].substr(Sindex+1); 
_http.setRequestHeader(key,value); 
} 
} 
_http.send(this.data); 
this.readyState = _http.readyState; 
if(_http.readyState==4){ 
this.status = parseInt(_http.status); 
this.http = _http; 
this.content = _http.responseBody; 
} 
return this; 
} 

_SmartHttp.prototype.getbinary=function(){ 
return this.content; 
}; 

_SmartHttp.prototype.gettext=function(charset){ 
try{ 
return this.b2s(this.content,charset ? charset : this.charset); 
}catch(ex){ 
this.msg = ex.description; 
return ""; 
} 
}; 

_SmartHttp.prototype.getjson=function(charset){ 
try{ 
var _json=null; 
eval("_json=(" + this.gettext(charset) + ");"); 
return _json; 
}catch(ex){ 
this.msg = ex.description; 
return null; 
} 
}; 

_SmartHttp.prototype.getheader=function(key){ 
if(key){ 
if(key.toUpperCase()=="SET-COOKIE"){ 
key = key.replace("-","/-"); 
var headers = this.http.getAllResponseHeaders(); 
var regexp = new RegExp("/n" + key + "/:(.+?)/r","ig"); 
var resstr = ""; 
while((res = regexp.exec(headers))!=null){ 
var val = res[1].trim(); 
resstr = resstr + val.substr(0,val.indexOf(";")) + "; " 
} 
if(resstr!=""){ 
resstr = resstr.substr(0,resstr.lastIndexOf(";")); 
} 
return resstr; 
}else{ 
return this.http.getResponseHeader(key); 
} 
}else{return this.http.getAllResponseHeaders();} 
}; 

_SmartHttp.prototype.getxml=function(charset){ 
try{ 
var _dom = new ActiveXObject("MSXML2.DOMDocument"); 
_dom.loadXML(this.gettext(charset)); 
return _dom; 
}catch(ex){ 
this.msg = ex.description; 
return null; 
} 
}; 
_SmartHttp.prototype.getobj = function (){ 
var b=null; 
var httplist = ["MSXML2.serverXMLHttp.3.0","MSXML2.serverXMLHttp","MSXML2.XMLHttp.3.0","MSXML2.XMLHttp","Microsoft.XMLHttp"]; 
for(var i = 0;i<=httplist.length -1;i++){ 
try{ 
b= new ActiveXObject(httplist[i]); 
(function(o){ 
_SmartHttp.prototype.getobj = function(){return new ActiveXObject(o)}; 
})(httplist[i]); 
return b; 
}catch(ex){ 
eval("this.msg = ex.description;"); 
} 
} 
return b; 
}; 

_SmartHttp.prototype.getrnd = function (){return Math.random().toString().substr(2);}; 

_SmartHttp.prototype.b2s = function(bytSource, Cset){ //ef bb bf,c0 fd 
var Objstream,c1,c2,c3; 
var byts; 
Objstream =Server.CreateObject("ADODB.Stream"); 
Objstream.Type = 1; 
Objstream.Mode = 3; 
Objstream.Open(); 
Objstream.Write(bytSource); 
Objstream.Position = 0; 
Objstream.Type = 2; 
Objstream.CharSet = Cset; 
byts = Objstream.ReadText(); 
Objstream.Close(); 
Objstream = null; 
return byts; 
}; 
_SmartHttp.prototype.urlencode=function(str){ return encodeURIComponent(str);}; 
_SmartHttp.prototype.urldecode=function(str){ return decodeURIComponent(str);}; 
String.prototype.trim = function(){return this.replace(/(^(/s+)|(/s+)$)/igm,"");}; 
</script>

<!--#include file="smart.asp"--> 
<% 
Response.charset="utf-8" 
dim url,method,data,charset 
url =Request.Form("targeturl") 
method =Request.Form("method") 
data =Request.Form("data") 
charset = Request.Form("charset") 
if charset = "" then charset = "GB2312" 
response.Write SmartHttp(url,method,data).send().gettext(charset) 
set myhttp = nothing 
%>