interface 

uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, OleCtrls, SHDocVw, ActiveX;  

type

  IDocHostShowUI = interface(IUnknown)

    ['{c4d244b0-d43e-11cf-893b-00aa00bdce1a}']

    function ShowMessage(hwnd: THandle; lpstrText: POLESTR; lpstrCaption: POLESTR;dwType: longint; lpstrHelpfile: POLESTR; dwHelpContext: longint;var plResult: LRESULT): HRESULT; stdcall;

    function ShowHelp(hwnd: THandle; pszHelpfile: POLESTR; uCommand: integer;dwData: longint; ptMouse: TPoint; var pDispatchObjectHit: IDispatch): HRESULT; stdcall;

  end;  

  TWebBrowser = class(SHDocVw.TWebBrowser,IDocHostShowUI)

  protected

    function ShowMessage(hwnd: THandle; lpstrText: POLESTR; lpstrCaption: POLESTR;dwType: longint; lpstrHelpfile: POLESTR; dwHelpContext: longint;var plResult: LRESULT): HRESULT; stdcall;

    function ShowHelp(hwnd: THandle; pszHelpfile: POLESTR; uCommand: integer;dwData: longint; ptMouse: TPoint; var pDispatchObjectHit: IDispatch): HRESULT; stdcall;

  end;  

type

  TForm1 = class(TForm)

    WebBrowser1: TWebBrowser;

    procedure FormCreate(Sender: TObject);

  private

    { Private declarations }

  public

    { Public declarations }

  end;  

var

  Form1: TForm1;  

implementation 

{$R *.dfm} 

{ TWebBrowser } 

function TWebBrowser.ShowHelp(hwnd: THandle; pszHelpfile: POLESTR; uCommand,

  dwData: Integer; ptMouse: TPoint; var pDispatchObjectHit: IDispatch): HRESULT;

begin

  Result := S_FALSE;

end;  

function TWebBrowser.ShowMessage(hwnd: THandle; lpstrText,

  lpstrCaption: POLESTR; dwType: Integer; lpstrHelpfile: POLESTR;

  dwHelpContext: Integer; var plResult: LRESULT): HRESULT;

begin

  //plResult := MessageBoxW(hwnd,PWChar(lpstrText),'Title',);//这里屏蔽了alert

  Result := S_OK;

end;  

procedure TForm1.FormCreate(Sender: TObject);

begin

  WebBrowser1.Navigate('E:/alert.htm');

end;  

end.