function WebText(WebBrowser:TWebBrowser):string;
var
  PersistStream: IPersistStreamInit;
  FileStream: TMemoryStream;
  Stream: IStream;
  SaveResult: HRESULT;
begin
  PersistStream := WebBrowser.Document as IPersistStreamInit;
  FileStream := TMemoryStream.Create;
  try
    Stream := TStreamAdapter.Create(FileStream, soReference) as IStream;
    SaveResult := PersistStream.Save(Stream, True);
    if FAILED(SaveResult) then begin
      Result:='Fail to save HTML source';
    end else begin
      SetLength(Result,FileStream.Size);
      move(FileStream.Memory^,Result[1],FileStream.Size);
    end; 
  finally
    FileStream.Free;
  end;
end;