如何在一个已经打开的jsp中用调整窗口风格？

没有办法。我最后的解决方法是：在被打开的窗口中加载自己写的ocx，先通过底层com方法获取当前IE窗口的IWebBrowser2对象，再调用IWebBrowser2的各种方法修改窗口的属性。下面是BCB开发的ocx的相关代码：  void __fastcall AdjustIEWindow(TRect WinSize, bool ShowMenu)
  {
    try {
      CComPtr<IOleContainer> iOct;
      OleCheck(m_spClientSite->GetContainer(&iOct));      CComQIPtr<IServiceProvider,&IID_IServiceProvider> iSpv(iOct);
      if(iSpv==NULL) return;      CComPtr<IServiceProvider> iSpvTop;
      OleCheck(iSpv->QueryService(SID_STopLevelBrowser, IID_IServiceProvider,
                                  reinterpret_cast<void **>(&iSpvTop)));
      if(iSpvTop==NULL) return;      CComPtr<IWebBrowser2> iWbs;
      OleCheck(iSpv->QueryService(SID_SWebBrowserApp, IID_IWebBrowser2,
                                  reinterpret_cast<void **>(&iWbs)));
      if(iWbs!=NULL)
      {
        try {
          HWND h=NULL;
          OleCheck(iWbs->get_HWND((long*)&h));
          if(h!=NULL) {
            ::ShowWindow(h,SW_SHOWNORMAL);
          }
        }
        catch(...) {
        }
        if(ShowMenu==false) {
          OleCheck(iWbs->put_ToolBar(false));
          OleCheck(iWbs->put_MenuBar(false));
        }
        OleCheck(iWbs->put_AddressBar(false));
        OleCheck(iWbs->put_Resizable(false));
        OleCheck(iWbs->put_Left(WinSize.Left));
        OleCheck(iWbs->put_Top(WinSize.Top));
        OleCheck(iWbs->put_Width (WinSize.Width()));
        OleCheck(iWbs->put_Height(WinSize.Height()));
      }
    }
    catch(...) {
    }
  }