I've linked the GitHub repo to this post - was frustrated that there was no JS alternatives for Benji Taylor's Agentation tool so I made one myself.

There's no installations - just link the script and you'll be good to go.

If you're interested in seeing how it will work with your site, here's a demo site that uses the tool. https://mearnest-dev.github.io/agentation-vanilla/demo/

Thought this may be helpful for someone out there - its open source so feel free to fork/clone/do whatever with it.