Adding html items

I have some html files on my computer which I would like to add as items to our Omeka site. I've seen that there is a possibility to add websites, but currently these files aren't available online.
Simply adding the html-files returns an error.
Is there a way to exhibit these files without needing to upload somewhere else first?
Thanks a lot!

Files of any kind can be added to items in Omeka. It might be that HTML files are blocked in the security settings, though, so that might be something to check.

What specific error are you getting?