Way back, before Java applets were as common as they are now, people experimented with writing plugins for various languages. I've seen at least one browser with a Python plugin, and I remember someone working on a Perl/Tk based browser that could do Perl plugins. And I certainly remember people talking about writing a Perl plugin.

But that's a long time ago, and I haven't heard anything about it in years, so it might very well be that their projects have died.

Did you do a Web search?