First Project :)

Hey, hope you guys are doing well. I'm new here and also to the community :p.
Here is something I coded as a beginner project.

See the Pen
ChatApp by WhiteWolfDot (@whitewolfdot)
on CodePen.

I know the code is not that great. Also I'm not good at back-end languages, someone please explain the best language I can use for this project. Thanks in advance.