[GTALUG] Which JavaScript should I learn?

Hi all, (If you're on KWLUG list, sorry for duplicate.) I have a general question about JavaScript. I want to develop/propose "web app" hosted from embedded Linux board. So, - you go to its webpage, - click "web app", - it will serve out JavaScript to browser client, and - the app will be running on the browser. Which Javascript should I learn? I mean, there are Meteor, Angular, React, Ember, Vue, etc. Some are described as "framework", and others described as "library". Then, there is Web Assembly I've been reading about recently. It's difficult to figure out what's what. -- William Park <opengeometry@yahoo.ca>