Comment by thayne

I worked on spell checking for a web app. It would have been really, really nice if there was just an API to interact with the browser spell checker. We couldn't use the spell check you get in a text area, because like google docs, we rendered the text ourselves and had a custom context menu. And we had very good reasons for doing those things.

However, I think it would be difficult to create such an API without leaking information about what words are in a users custom dictionary (which could be used for fingerprinting). And allowing an app to add custom words would probably have some security implications.

Maybe if there was an API to open a spell check popup that was native to the browser and the only info you get is what word (if any) they chose to replace. But, besides having a suboptimal UX, that doesn't help you know which words to highlight as misspelled.