Firefox includes a built-in spellchecker that lets you know when you're misspelling words in an email or other text entry box. But what if you want to spellcheck an email that's already been sent or a web site that's already been published. In Firefox it is simple......Type
into your address bar. If you find it useful, I recommend that you store that code as a bookmark, I call it Spell Check for example.
Of course any changes will not be stored and any changes would be gone the next time you load the page, BUT still immensley useful for proofreading etc....