function ExJS(var wb: TWebBrowser; jStr: string): string;
var
  Doc: IHTMLDocument2;
  HTMLWindow: IHTMLWindow2;

begin
  try
    begin
      wb.Document.QueryInterface(IHTMLDocument2, Doc);
      HTMLWindow := Doc.parentWindow;

      HTMLWindow.execScript(jStr, 'JavaScript');
      result := (wb.Document as IHTMLDocument2).body.innerHTML;
    end;
  except
    on e: Exception do
       log(0,0,'ERR','ExJS:'+e.Message);
  end;

end;

//webBrowser1DocumentComplete
ExJS(w, '  setInterval(function(){window.onbeforeunload = null;},5); ');

//webBrowser1DownloadBegin   
ExJS(w, '  setInterval(function(){window.onbeforeunload = null;},5); ');