Now on tmtest, an experiment with findroute to try to speed up filtering. Instead of building the whole table and using each row's display property to show or hide it, I just rebuild the whole body of the table each time. On my browsers, it seems to speed things up somewhat when lots of routes are displayed (no or very limited filtering), and speeds things up a lot when fewer routes are displayed (more restrictive filters).
See what you think, but I'll probably make this the production version very soon.