#HTTP_QUERY_CONTENT_LENGTH=5

Procedure.q GetContentLength(Url$)
  Protected FileSizet.s=Space(20),FileSize.q, Size,hINET,hURL
  hINET=InternetOpen_("blub",0,0,0,0)
  If hINET
    hURL =InternetOpenUrl_(hINET,Url$,0,0,$80000000,0)
    If hURL
      Size=Len(FileSizet)
      HttpQueryInfo_(hURL,#HTTP_QUERY_CONTENT_LENGTH,@FileSizet,@Size,#Null)
      FileSize=Val(FileSizet)
      InternetCloseHandle_(hURL)
      InternetCloseHandle_(hINET)
    Else
      InternetCloseHandle_(hINET)
    EndIf
  EndIf
  ProcedureReturn FileSize
EndProcedure

MessageRequester("","Dateigröße: "+Str(GetContentLength("http://www.rsbasic.i3h.de/downloads/auto_desktop_background_changer.zip"))+" Bytes",0)