As is, the library sort of works, but there are two specific changes/fixes we need made.
1. When the user selects a string to replace a misspelled word, the replacement actually occurs at the first instance of the substring, rather than replacing the actual misspelled word. This needs to be fixed so the word that is actually misspelled is the one replaced by the selected replacement string.
2. The spell checker tends to ignore misspelled words if the user is typing sufficiently fast, or if text is copied+pasted into a text field. This needs to be fixed as well.
Spellify can be downloaded for free here:
[url removed, login to view]
You'll find everything you need in the ZIP file there, but you'll need a few things to do the development, namely a server environment that runs PHP 4 or higher with cURL enabled. Scriptaculous and Prototype come with the ZIP file.