procedure TForm1.Button2Click(Sender: TObject); 
var 
  i: Integer; 
begin 
  Listbox1.Clear; 
  //if frames available 
  if Webbrowser1.OleObject.Document.Frames.Length <> 0 then 
  begin 
    //walk through all frames and get the url 
    //to the Listbox 
    for i := 0 to Webbrowser1.OleObject.Document.Frames.Length - 1 do 
    begin 
      Listbox1.Items.Add(Webbrowser1.OleObject.Document.Frames.item(i).Document.URL); 
    end; 
  end; 
end;