Firefox 3 comes with a handy-dandy built-in spelling checker. If you've ever used, say, Google Docs or posted a message in an online forum, you've probably seen it at work: A red line appears under each misspelled word. You right-click the word to see spelling suggestions (along with the usual context-menu options).

It's a great feature, but it has one shortcoming: It doesn't work in Web forms. Well, not yet, anyway. But it's a simple matter to tweak the spelling checker so that it pulls form duty as well.

Open Firefox, type about:config in the address bar, and press Enter. In the Filter field, type spellcheek. Right-click layout.spellcheckDefault, and click Modify. Raise the value from 1 to 2. Restart Firefox. The spelling checker should now work in most online forms.