我遇到的问题： 内嵌IE浏览器控件WebBrowser的内嵌页host.html中使用iframe又嵌套了一个页面iframe.html，iframe.html上有个JS方法，我用C++调用不到，而host.html上的JS方法可以正常调用到。
问题分析： 从JS来说，这是个跨域问题，host.html和iframe.html不在一个域内； JS解决跨域问题的方案其实也是有的，但这个不是我们本文的重点，本文的重点是怎么通过WebBrowser控件直接来解决这个“跨域调用”的问题。
问题的根本原因在于： 调用网页的JS需要拿到IHTMLDocument2接口，而每个iframe都有自己对应的IHTMLDocument2，所以我们只要能拿到iframe对应的IHTMLDocument2就能解决问题了。
解决方案：直接上代码吧

/* -------------------------------------------------------------------------
//    FileName    :    calljs_helper.h
//    Creator        :    linyehui
//    Date        :    2013/11/16 01:18:09
//    Brief        :    调用WebBrowser控件内嵌页上的JS函数，iframe中的也能调到
//
//    $Id: $
// -----------------------------------------------------------------------*/
#ifndef __CALLJS_HELPER_H__
#define __CALLJS_HELPER_H__
// -------------------------------------------------------------------------
namespace calljs_helper
{
    bool CallFunction(
        CComPtr<IWebBrowser2> spIWebBrowser, 
        LPCTSTR lpFuncName,
        const vector<wstring>& paramArray, 
        CComVariant * pVarResult = NULL,
        bool bEnumFrame = true);
} // namespace
// -------------------------------------------------------------------------
// $Log: $
#endif /* __CALLJS_HELPER_H__ */

/* -------------------------------------------------------------------------
//    FileName    :    calljs_helper.cpp
//    Creator        :    linyehui
//    Date        :    2013/11/16 01:18:14
//    Brief        :    调用WebBrowser控件内嵌页上的JS函数，iframe中的也能调到
//
//    $Id: $
// -----------------------------------------------------------------------*/
#include "stdafx.h"
#include "calljs_helper.h"
// -------------------------------------------------------------------------
CComPtr<IWebBrowser2> HtmlWindowToHtmlWebBrowser(CComPtr<IHTMLWindow2> spWindow)
{
    ATLASSERT(spWindow != NULL);
    CComQIPtr<IServiceProvider>  spServiceProvider = spWindow;
    if (spServiceProvider == NULL)
    {
        return CComPtr<IWebBrowser2>();
    }
    CComPtr<IWebBrowser2> spWebBrws;
    HRESULT hRes = spServiceProvider->QueryService(IID_IWebBrowserApp, IID_IWebBrowser2, (void**)&spWebBrws);
    if (hRes != S_OK)
    {
        return CComPtr<IWebBrowser2>();
    }
    return spWebBrws;
}
// Converts a IHTMLWindow2 object to a IHTMLDocument2. Returns NULL in case of failure.
// It takes into account accessing the DOM across frames loaded from different domains.
CComPtr<IHTMLDocument2> HtmlWindowToHtmlDocument(CComPtr<IHTMLWindow2> spWindow)
{
    ATLASSERT(spWindow != NULL);
    CComPtr<IHTMLDocument2> spDocument;
    HRESULT hRes = spWindow->get_document(&spDocument);
    if ((S_OK == hRes) && (spDocument != NULL))
    {
        // The html document was properly retrieved.
        return spDocument;
    }
    // hRes could be E_ACCESSDENIED that means a security restriction that
    // prevents scripting across frames that loads documents from different internet domains.
    CComPtr<IWebBrowser2> spBrws = HtmlWindowToHtmlWebBrowser(spWindow);
    if (spBrws == NULL)
    {
        return CComPtr<IHTMLDocument2>();
    }
    // Get the document object from the IWebBrowser2 object.
    CComPtr<IDispatch> spDisp;
    hRes = spBrws->get_Document(&spDisp);
    spDocument = spDisp;
    return spDocument;
}
bool CallFunctionInDocument(
                            CComPtr<IHTMLDocument2> spDocument2, 
                            LPCTSTR lpFuncName,
                            const vector<wstring>& paramArray, 
                            CComVariant * pVarResult)
{
    if (!spDocument2)
        return false;
    CComPtr<IDispatch> spScript; 
    if (FAILED(spDocument2->get_Script(&spScript))) { return false; }
    CComBSTR bstrMember(lpFuncName); 
    DISPID dispid = NULL; 
    HRESULT hr = spScript->GetIDsOfNames(IID_NULL, &bstrMember, 1, LOCALE_SYSTEM_DEFAULT, &dispid); 
    if (FAILED(hr)) { return false; }
    const int arraySize = paramArray.size(); 
    DISPPARAMS dispparams; 
    memset(&dispparams, 0, sizeof dispparams); 
    dispparams.cArgs = arraySize; 
    dispparams.rgvarg = new VARIANT[dispparams.cArgs]; 
    for (int i = 0; i < arraySize; i++)
    {
        CComBSTR bstr = paramArray[arraySize - 1 - i].c_str(); // back reading
        bstr.CopyTo(&dispparams.rgvarg[i].bstrVal); 
        dispparams.rgvarg[i].vt = VT_BSTR; 
    }
    dispparams.cNamedArgs = 0; 
    EXCEPINFO excepInfo; 
    memset(&excepInfo, 0, sizeof excepInfo); 
    CComVariant vaResult; 
    UINT nArgErr = (UINT)-1;  // initialize to invalid arg
    hr = spScript->Invoke(dispid, IID_NULL, 0, DISPATCH_METHOD, &dispparams, &vaResult, &excepInfo, &nArgErr); 
    delete [] dispparams.rgvarg; 
    if (FAILED(hr)) { return false; }
    if (pVarResult) { *pVarResult = vaResult; }
    return true;
}
void EnumFrame(
                              CComPtr<IHTMLDocument2> spIHTMLDocument2, 
                              LPCTSTR lpFuncName,const vector<wstring>& paramArray, 
                              CComVariant* pVarResult)
{
    if ( !spIHTMLDocument2 )
        return;
    CComPtr< IHTMLFramesCollection2 > spFramesCollection2;
    spIHTMLDocument2->get_frames( &spFramesCollection2 );
    long nFrameCount=0;
    HRESULT hr = spFramesCollection2->get_length( &nFrameCount );
    if ( FAILED ( hr ) || 0 == nFrameCount )
        return;
    for(long i = 0; i < nFrameCount; i++)
    {
        CComVariant vDispWin2;
        hr = spFramesCollection2->item( &CComVariant(i), &vDispWin2 );
        if ( FAILED ( hr ) ) 
            continue;
        CComQIPtr< IHTMLWindow2 > spWin2 = vDispWin2.pdispVal;
        if( !spWin2 )
            continue;
        CComPtr < IHTMLDocument2 > spDoc2;
        spDoc2 = HtmlWindowToHtmlDocument(spWin2);
        if (!spDoc2)
            continue;
        CallFunctionInDocument(spDoc2, lpFuncName, paramArray, pVarResult);
    }
}
bool calljs_helper::CallFunction(
                  CComPtr<IWebBrowser2> spIWebBrowser, 
                  LPCTSTR lpFuncName,
                  const vector<wstring>& paramArray, 
                  CComVariant * pVarResult,
                  bool bEnumFrame)
{
    if (!spIWebBrowser) 
        return false;
    CComPtr<IDispatch> spDispDoc; 
    HRESULT hr = spIWebBrowser->get_Document(&spDispDoc); 
    if (FAILED(hr))
        return false;
    CComQIPtr<IHTMLDocument2> spDocument2 = spDispDoc; 
    if (!spDocument2)
        return false;
    CallFunctionInDocument(spDocument2, lpFuncName, paramArray, pVarResult);
    
    if (bEnumFrame)
    {
        EnumFrame(spDocument2, lpFuncName, paramArray, pVarResult);
    }
    
    return true; 
}
// -------------------------------------------------------------------------
// $Log: $

 

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