JavaScript
Free resources of lectures -
Application -
Note: you will learn more either by googling yourselves or exploring the topic yourselves you can't learn as much from others experience as you learn from yours.1.Web Development
JS is like brain for a website, by using JS you will able to design any thing that you can't do with help of css, it provide functionalty to a button or tell website what to do at given state.
2.Backend Development
Yup, you heard write JS is used also for backend development, Node.js that provide a run time enviroment for javaScript.
3.Mobile Application
React.js and React native these two are frameworks of JS that is developed by facebook and many popular apps have been developed in React native like instagram, fb, Bloomberg. It provides simplicity of developing apps for multiple paltform simultaneously.