Using chromeless popup

Hi,
I have tried using the chromeless popup from http://www.kirupa.com/developer/mx2004/chromeless.htm and it works perfectly in all versions of IE. However in netscape, although the popup opens, no content appears (It also has the title bar, but that is not a major problem)
Is there any way to get the content to appear in netscape - maybe by using some sort of browser detection?

Thanks

JennyJ