I'm gonna opt against it, namely because spelling varies by country (and in some cases, even region of country), and all modern browsers have spell check built in. It'd be a waste of effort to build it in when its already there for the majority of people, and then I'd have to build in a dictionary that accommodates every country, and then again for the fact that each game has made up words. Things would be haywire all over the place.
You can always modify the dictionary on your browser to check for and correct any words you think should be.