Silverlight Browser Windows Communcation

I got this email some time ago but it was in my junk email box. Anyway I finally found it and thought it might be of use to everyone.

Hi DavidThanks for your posting on SilverLight. It helps me a lot.Now I have a challenge technical problem:I have a HTML page as parent window that plays some video clip. Also people can click a link from that page to create some popup windows (child windows). In the child windows, the same video clip from the parent window should be played (content sync).I can do this using a common XAML file that shared among these windows.Now the challenge for me is: the parent window has video control buttons (like play, pause, stop, ...). How to sync the action controls? For example, if the video is stopped in the parent window, the stop should also apply to all child windows. In other words, how to achieve the action sync?I am thinking if it is possible to change the XAML by the parent window on the fly so that child windows can be updated accordingly. I am not sure if this is possible in Silverlight since it seems to me the XAML is a static object. Can you think of a way to accomplish that or shed some light on the issue?
Thanks! Jay
my response:

you would need hold a reference to the child window and call into it from script so basically when you click a button in the parent it would also go call out to script and the child window. For doing this in IE MSDN has a good reference on working with the IE object model to do this. Start by finding window.open and how to keep a reference and make calls. This however I don't think is very cross browser...