Why pass array from CDhtmlDialog to javascript fail

Dear All
   I have used a CDhtmlDialog to show html page, currently, I will call
window.external function in javascript. and return some data back to
javascript. however, It will fail.

code snippet is below

VARIANT CMyHtmlDlgDlg::GetSrInfo()
{
    HRESULT hr = E_FAIL;
    VARIANT stVar;
 CComSafeArray<VARIANT> m_oArrSrInfo;

    ::VariantInit(&stVar);
    V_VT(&stVar) = VT_EMPTY;

    m_oArrSrInfo.Add(CComVariant(1));
 m_oArrSrInfo.Add(CComVariant(2));
 m_oArrSrInfo.Add(CComVariant(3));

    V_VT(&stVar) = VT_ARRAY | VT_VARIANT;
    V_ARRAY(&stVar) = m_oArrSrInfo;

    return stVar;
}

javascript:
function UpdateInfo() {
 alert('Before GetSrInfo');
 var objArrayInfo = new VBArray(window.external.GetSrInfo()); //Line 1
 alert('After GetSrInfo');
}
when call UpdateInfo(), Line 1 will pop javascript error : invalid procedure
call or argument.
and I have return a uint or BSTR, The javascript will work, only when return
a array, It will fail, Please give me some suggestion. Thanks!

---------------------------------------------------------------------------------------
I have call SetExternalDispatch(GetIDispatch(TRUE));
CMyDHTMLDialog::OnInitDialog, and call EnableAutomation in constructor
function. I wanna know what other should I do for CDHtmlDialog.
  By the way, As I have described in first post, I have used the same way to
return a string,

//C++ code
VARIANT CMyHtmlDlgDlg::GetString()
{
 VARIANT varStr;
 BSTR bstr;
 bstr = SysAllocString(L"hello");
 ::VariantInit(&varStr);
 V_VT(&varStr) = VT_BSTR;
 V_BSTR(&varStr) = bstr;

 SysFreeString(bstr);
 return varStr;
}

//Javascript code
function GetMsg() {
 var strMsg = window.external.GetString();
 document.getElementById("MsgBtn").value = strMsg;
}

For this function, Javascript can return correct value, It only has problem
when I return a Array, Thanks!!

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