IHTMLElement setAttribute does not refresh

Question

The following vc++ code the display is not reflected. I use IWebBrowser2 component.

`// CComQIPtr pElement id=test; //

VARIANT_BOOL res;
CComBSTR temp(newData.c_str());
vtVariant.vt=VT_BSTR;
vtVariant.bstrVal=temp;
pElement->setAttribute((CComBSTR)"Value",vtVariant);

I can get Value newData from getAttribute.