delphi 向webbrowser打开的网页中插入js命令

unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, OleCtrls, SHDocVw, ExtCtrls,MSHTML;
type
TForm1 = class(TForm)
    Panel1: TPanel;
    Panel2: TPanel;
    Edit1: TEdit;
    Button1: TButton;
    WebBrowser1: TWebBrowser;
    WebBrowser2: TWebBrowser;
    Button2: TButton;
    Memo1: TMemo;
    procedure Button1Click(Sender: TObject);
    procedure WebBrowser1NewWindow2(Sender: TObject; var ppDisp: IDispatch;
      var Cancel: WordBool);
    procedure WebBrowser2BeforeNavigate2(Sender: TObject;
      const pDisp: IDispatch; var URL, Flags, TargetFrameName, PostData,
      Headers: OleVariant; var Cancel: WordBool);
    procedure Button2Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
private
    { Private declarations }
public
    { Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.Button1Click(Sender: TObject);
begin
    webbrowser1.Navigate(edit1.Text );
end;
procedure TForm1.WebBrowser1NewWindow2(Sender: TObject;
var ppDisp: IDispatch; var Cancel: WordBool);
begin
    ppDisp := WebBrowser2.Application;
end;
procedure TForm1.WebBrowser2BeforeNavigate2(Sender: TObject;
const pDisp: IDispatch; var URL, Flags, TargetFrameName, PostData,
Headers: OleVariant; var Cancel: WordBool);
begin
    WebBrowser1.Navigate(string(URL)); // 再指回WebBrowser1
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
(WebBrowser1.Document as IHTMLDocument2).parentWindow.execScript(
   memo1.text, 'javascript')
end;
procedure TForm1.FormCreate(Sender: TObje