1、只要在ajax中有数据提交时，如果页面编码不是utf-8的，都应该对提交的数据进行编码，js的编码函数为escape()
2、在服务器端页接收数据后进行解码，然后对数据进行相关的处理后再编码
3、返回到客户端后再解码
4、如果没有提交数据，而是直接从服务器端获取数据，那直接在服务器页面设置Response.Charset="gb2312"即可，不用再编码解码
vbscript中分别对应js中的escape()和unescape()函数

程序代码
<%
          '与javascript中的escape()等效
    Function VbsEscape(str)
        dim i,s,c,a
        s=""
        For i=1 to Len(str)
            c=Mid(str,i,1)
            a=ASCW(c)
            If (a>=48 and a<=57) or (a>=65 and a<=90) or (a>=97 and a<=122) Then
                s = s & c
            ElseIf InStr("@*_+-./",c)>0 Then
                s = s & c
            ElseIf a>0 and a<16 Then
                s = s & "%0" & Hex(a)
            ElseIf a>=16 and a<256 Then
                s = s & "%" & Hex(a)
            Else
                s = s & "%u" & Hex(a)
            End If
        Next
        VbsEscape=s
    End Function
    '与javascript中的unescape()等效
    Function VbsUnEscape(str)
                    Dim x
        x=InStr(str,"%")
        Do While x>0
            VbsUnEscape=VbsUnEscape&Mid(str,1,x-1)
            If LCase(Mid(str,x+1,1))="u" Then
                VbsUnEscape=VbsUnEscape&ChrW(CLng("&H"&Mid(str,x+2,4)))
                str=Mid(str,x+6)
            Else
                VbsUnEscape=VbsUnEscape&Chr(CLng("&H"&Mid(str,x+1,2)))
                str=Mid(str,x+3)
            End If
            x=InStr(str,"%")
        Loop
        VbsUnEscape=VbsUnEscape&str
    End Function
%>
来个演示：

客户端页:client.html

程序代码
<script>
    //jquery的post
    $.post
    (
        'server.asp',
        {
            Act:'DoSubmit',
            UserName:escape('西楼冷月'),//进行编码
           WebSite:'www.chinacms.org'
        },
        function(data)
        {
            alert(unescape(data));//对返回数据进行解码
        }
    );
    
</script>

服务器端页:server.asp
程序代码
<%
                Response.Charset="gb2312"
    Dim UserName,WebSite
    If Request.Form("Act")="DoSubmit" Then
                               UserName=Request.Form("UserName")
        WebSite =Request.Form("WebSite")

        '在服务器端解码
        UserName=VbsUnEscape(UserName)//解码

        '处理数据
        '---省略数据处理部分

        '数据处理后输出，先用VbsEscape()编码
        'by www.chinacms.org
        Response.Write VbsEscape(UserName)
    End If
%>