ASP simple to prevent external submissions

' ****************************************************
  ' function name: chkpost
  ' for   use: Prohibit outbound submission of form
  ' return value: True station submitted, outside Flase station
  ' ****************************************************
  public Function chkpost ()
   Dim url1,url2
   chkpost=true
   url1=cstr ( Request.ServerVariables ("Http_referer"))
   url2=cstr (Request.ServerVariables ("SERVER_NAME"))
   If Mid (Url1,8,len (URL2)) <>url2 and InStr (URL1, "dl.loupan.com") = 0 Then
  chkpost= False
  exit function
   end If
  End Function

  ' ****************************************************
  function name: GETURL
  ' for   Use: Get URL including parameter
  ' return value: Get URL including parameter
  ' ****************************************************
  Public Function GetUrl ()   
   Dim strtemp    
   strtemp= Request.ServerVariables ("Script_name")      
   if  Trim ( request.querystring) <> "" Then
    strtemp=strtemp& "?"
    for each m_item in request.querystring
  strTemp=strTemp&M_item& "=" &server.urlencode (Trim (Request.QueryString ("&M_item&"))
    next
    End If
   geturl=strtemp  
  End Function
 
  ' Prevent external submission usage
 call chkpost () '