Google map

Google map
I have that code which is ok

    WebBrowser1.Navigate('about:blank');
    while WebBrowser1.ReadyState <> READYSTATE_COMPLETE do
    begin
      Application.ProcessMessages;
      Sleep(0);
    end;
    if Assigned(WebBrowser1.Document) then
    begin
      aStream.Clear;
      try
        aStream.WriteBuffer(Pointer(HTML)^, Length(HTML));
        aStream.Seek(0, soFromBeginning);
        (WebBrowser1.Document as
          IPersistStreamInit).Load(TStreamAdapter.Create(aStream, soReference));
      finally
               aStream.Free;
      end;

on document complete i do... it is ok

procedure TForm1.WebBrowser1DocumentComplete(Sender: TObject;
  const pDisp: IDispatch; var URL: OleVariant);
begin
       HTMLWindow2 := (WebBrowser1.Document as IHTMLDocument2).parentWindow;

the problem is that i want to  execute the script automatically.

HTMLWindow2.execScript('SetMyMap()', 'JavaScript');

if i execute it with a button it is ok but not after  HTMLWindow2 :=...
It seems that  HTMLWindow2 := takes TIME.
Where do i put it?and what condition to check to execute
AUTOMATICALLY. 
I need to load google.maps.Polyline the moment i load the map.
The HTML is ok no problem.