A place to store lots of code snippets so that you can easily find them.
First, put it in the folder of the language you're working in (JS working on HTML should go in the JavaScript folder and CSS likewise - however use discretion). Then add a new subfolder for your snippet. It can be a good idea to provide the snippet, a working example and a README.md
(as this will explain it nicely in the github folder).
Also, here, more than anywhere, comment your code! Being able to understand and improve other people's code is one of the best ways to learn.