To put it simply:
-JavaScript is the programming language of HTML and the Web.
-JavaScript is easy to learn.

And a JavaScript framework is an application framework written in JavaScript where the programmers can manipulate the functions and use them for their convenience.
So here are a few lesser known JavaScript frameworks (opinion!) that you should check out.

https://www.polymer-project.org/

https://emberjs.com/

https://www.electronjs.org/

https://www.meteor.com/

https://backbonejs.org/