Using just-uploaded Mozilla::DOM 0.04 and the small attached patch against CVS HEAD of Gtk2::MozEmbed, you can access the DOM Window with $browser = $embed->get_nsIWebBrowser(); $window = $browser->get_content_domwindow(); (Please see the XXX in pumzilla for a segfault problem, though.) It isn't very functional yet, but it's getting there.
Attachment:
gtk2mozembed.diff
Description: diff against CVS HEAD