Seriously, I think that Tk is out of the running for browser based displays, for all the reasons you mentioned.

I think that gtk3 may be the way. Why? Because firefox and many other open source browsers are currently gtk2/gtk3 based. That means that under the hood, they both would utilize the same signals and callback system.

It looks like Python is moving forward with pyXPCOM and similar interfaces, and IIRC there is a configure option in the newer mozilla browsers to enable experimental Python support.

It seems to me that Perl needs to get involved with XPCOM. It currently has C, C++, Python and Ruby. Where's Perl?

Of course, I find the whole desire to run everything in a web browser rather disgusting, resulting in code bloat and html/javascript which is as hard to read as assembly language.

In my little world, I would rather write custom scripts for clients to connect, vis ssh, keeping the browser and http servers out of it all together. :-)