asp检测文件编码

function checkcode(path)
set objstream=server.createobject("adodb.stream")
objstream.Type=1
objstream.mode=3
objstream.open
objstream.Position=0
objstream.loadfromfile path
bintou=objstream.read(2)
If AscB(MidB(bintou,1,1))=&HEF And AscB(MidB(bintou,2,1))=&HBB Then
checkcoder="utf-8"
ElseIf AscB(MidB(bintou,1,1))=&HFF And AscB(MidB(bintou,2,1))=&HFE Then
checkcode="unicode"
Else
checkcode="gb2312"
End If
objstream.close
set objstream=nothing
end function