Somebody has finally taken a stab at creating a plugin that's been on my Mozilla wish-list for a long time: An HTML validator that perfoms on-the-fly validation of every page the browser loads without sending anything to a 3rd party. It uses the tried-and-true tidy engine for the heavy lifting, and prints a nice little "N errors / N warnings" in the corner of the status bar.

The downside: It's buggy. When I open the window that's supposed to show what the errors are, the combo box always comes up blank. Doh! (Maybe if I get ambitious, I'll try and debug it.) Even with this handicap, I find it very useful to inform me of the existence of errors on my pages while I'm browsing, and I can then run tidy manually to find out where the errors are.

If and when the kinks get worked out, this plugin deserves an award of some sort.