IWebBrowser2* CxCtrl::GetWebPointer()
{
    HRESULT hr;
    IOleContainer* pIContainer;
    IWebBrowser2* pIWeb;
    IServiceProvider *pISP;
    
    // get IOleClientSite interface pointer.

    LPOLECLIENTSITE pIClientSite = GetClientSite();
    
    // get IOleContainer interface poineter.

    hr = pIClientSite->GetContainer(&pIContainer);
    if( hr != S_OK )
    {
        pIClientSite->Release();
        return NULL;
    }
    
    // get IServiceProvider interface pointer.

    hr = pIClientSite->QueryInterface( IID_IServiceProvider, (void **)&pISP );
    if( hr != S_OK )
    {
        pIContainer->Release();
        pIClientSite->Release();// access violation when terminated.
        return NULL;
    }

    // get IWebBrowser2 interface pointer.

    hr = pISP->QueryService( IID_IWebBrowserApp, IID_IWebBrowser2, (void**)&pIWeb );
    if( hr != S_OK )
    {
        pIContainer->Release();
        pIClientSite->Release();
        pISP->Release();
        return NULL;
    }
    
    // release interface.

    pIContainer->Release();
    pIClientSite->Release();
    pISP->Release();

    return pIWeb ;
}