字符乱码解决方法

用Post方法提交数据时，提交了一个很长的字符串，总是提示没有权限。
var objhttp= new ActiveXObject("msxml2.xmlhttp");
objhttp.open("Post","jzh_receive.aspx?jzh="+strxml,false);
objhttp.send();
zbzy=objhttp.responsetext
strxml长度不固定

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objhttp.open("Post","jzh_receive.aspx?jzh="+strxml,false);
strxml数据很长，不应该用这种方法，用
strA = "submit1=Submit&text1=scsdfsd";//Looks like QueryString,But there's no "?" here!
var oReq = new ActiveXObject("MSXML2.XMLHTTP");
oReq.open("POST","jzh_receive.aspx",false);
oReq.setRequestHeader("Content-Length",strA.length);
oReq.setRequestHeader("CONTENT-TYPE","application/x-www-form-urlencoded");//没有这句就玩不转拉
oReq.send(strA);

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http://dotnet.aspx.cc/ShowDetail.aspx?id=ATV1GLXT-65FF-4M82-CT5U-B1J65D3ZN2OK

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TO:net_lover(孟子E章)
提交到服务器端后汉字全变成了乱字符，怎么解决？？？

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strA = "submit1=Submit&text1="+strxml;
var oReq = new ActiveXObject("MSXML2.XMLHTTP");
oReq.open("POST","jzh_receive.aspx",false);
oReq.setRequestHeader("Content-Length",strA.length);
oReq.setRequestHeader("CONTENT-TYPE","application/x-www-form-urlencoded");
孟先生提供的这个方法可以，但是提交到服务端后出现乱字符。
孟先生又给了下面这个方法，但是下面这段代码，怎么加到上面代码里？
xmlhttp.setRequestHeader("Content-Type","text/xml")
<%
Response.ContentType = "text/xml"
Response.CharSet = "GB2312"
%>

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直接加在當前頁面的頂部。