public IWebBrowser2 GetBrowserFromWindow(IHTMLWindow2 win)

{

  if(win == null)

  {

    throw new ArgumentNullException("win");

  }

  IWebBrowser2 result = null;

  //if the document is the top level document, we don't have to look for it

  if(win.document == this.CurrentDocument)

  {

    result = this.IWebBrowser2; //internal reference to the top-level IWebBrowser2

  }

  else

  {

    //get the OLE container from the window's parent

    IOleContainer oc = win.parent.document as IOleContainer;      //OC ALLOC

    //get the OLE enumerator for the embedded objects

    int hr = 0;

    IEnumUnknown eu;

    hr = oc.EnumObjects(tagOLECONTF.OLECONTF_EMBEDDINGS, out eu); //EU ALLOC

    Marshal.ReleaseComObject(oc);                                 //OC FREE

    Marshal.ThrowExceptionForHR(hr);

    Guid IID_IWebBrowser2 = typeof(SHDocVw.IWebBrowser2).GUID;

    object pUnk = null;

    int fetched = 0;

    const int MAX_FETCH_COUNT = 1;

    //get the first embedded object

    hr = eu.Next(MAX_FETCH_COUNT, out pUnk, out fetched);         //PUNK ALLOC

    Marshal.ThrowExceptionForHR(hr);

    //while sucessfully get a new embedding, continue

    for(int i = 0; HRESULTS.S_OK == hr; i++)

    {

      //QI pUnk for the IWebBrowser2 interface

      SHDocVw.IWebBrowser2 brow = pUnk as SHDocVw.IWebBrowser2;

      if(brow != null)

      {

        //if the document for this browser matches the one passed in, we found it

        if(brow.Document == win.document)

        {

          result = brow;

          break;

        }

        else

        {

          Marshal.ReleaseComObject(brow);                         //PUNK FREE

        }

      } //if(brow != null)

      //get the next ebmedded object

      hr = eu.Next(MAX_FETCH_COUNT, out pUnk, out fetched);       //PUNK ALLOC

      Marshal.ThrowExceptionForHR(hr);

    } //for(int i = 0; HRESULTS.S_OK == hr; i++)

    Marshal.ReleaseComObject(eu);                                 //EU FREE

  }

  return result;

}