Node.js

[Versus]

Is there anybody who can briefly explain how it works? I would really appreciate simple explanation because info I find in the internet is really hard to understand for a person who has never dealt with it.

[Krispy Kritter]

It's a java script environment.

Ref here: https://en.wikipedia.org/wiki/Node.js

If you don't understand the basics of the wiki, I don't know what to tell you.