怎么控制html中的TextArea标签

//发帖
void CPHPWINDDlg::OnButtonPost() 
{
    // TODO: Add your control notification handler code here
    LPDISPATCH      lpDispatch = NULL;
    HRESULT         hr    = NULL;  
    long nElemCount = 0;

    CComPtr <IHTMLDocument2> lpHtmlDoc2  = NULL;   
    CComQIPtr< IHTMLElementCollection > spElementCollection;
    CComPtr <IHTMLFramesCollection2> lpHtmlFramesCollection2 = NULL;
    CComPtr <IHTMLFormElement>  lpHtmlFormElement = NULL;
    CComQIPtr <IHTMLElement> lpElem;

    //A:得到文档
    lpDispatch = m_Browser.GetDocument();
    hr   = lpDispatch->QueryInterface(IID_IHTMLDocument2, (void**)&lpHtmlDoc2);   
    if (hr != S_OK )
    {
        AfxMessageBox("失败:lpDispatch->QueryInterface!");
        return;
    }

    USES_CONVERSION;
    
    hr = lpHtmlDoc2->get_all( &spElementCollection );
    if (hr != S_OK)
    {
        AfxMessageBox("lpHtmlDoc2->get_all");
    }
    
    hr = spElementCollection->get_length( &nElemCount );
    if (hr != S_OK)
    {
        AfxMessageBox("获取元素个数失败");
    }

    long j = 0;
    VARIANT name;
    name.vt = VT_I4; 

    for(long i=0; i<nElemCount; i++)
    {
        name.lVal = i;
        hr = spElementCollection->item( name,name,&lpDispatch);
        if (hr != S_OK)
        {
            AfxMessageBox("spElementCollection->item");
        }

        hr = lpDispatch->QueryInterface(IID_IHTMLElement, (void**)&lpElem); 
        if (hr != S_OK)
        {
            AfxMessageBox("lpDispatch->QueryInterface");
        }
        
        
        BSTR tag;
        CString strTag = "TEXTAREA";
        lpElem->get_tagName(&tag);
        CString tempTag = tag;
        tempTag.MakeUpper();
        
        CComQIPtr<IHTMLTextAreaElement> TextArea;
        if (tempTag == strTag)
        {
            //AfxMessageBox("找到了");
        
            hr = lpElem->QueryInterface(IID_IHTMLTextAreaElement, (void**)&TextArea); 
            if (hr != S_OK)
            {
                AfxMessageBox("lpElem->QueryInterface");
            }

            lpElem->click();
            TextArea->select();
            TextArea->put_value(strTag.AllocSysString());
        }
    }
}