Typo is a browser based spell check program - it was written to be as simple and as flexible as possible.
It doesn't depend on any libraries and is quiet robust - importantly it can run independently in the browser (even locally).
* Very easy to add in extra features, to identify synonyms and weak words.
* Can be optimized to load libraries/dictionaries on the fly
* The lookup system can be improved to use a binary search for example (performance)
* Just for fun, there is interactive editor below, so you can type in words - error words are highlighted yellow
Try typing some words here run them through the Typo checker: