JavaScript is the high-level, weak-type, multi-paradigm, and interpreted language used to make web pages dynamic and interactive at its core.
There are several other benefits of learning it as a beginner, intermediate or expert.

1. No compiler or Interpreter is required

JavaScript is supported by all browsers like Internet Explorer, Mozilla Firefox, Google Chrome, Safari, and Opera etc.
We do not need to install any third party software (compiler or interpreter) to compile and execute its code.
We only require a notepad in which we can write JavaScript code and execute it directly into any browser.

2. Weak-Type Programming Language

JavaScript is the weak-type language unlike other strong-type programming languages like Java and C++, which have strict rules for coding and beginners face many problems and find these languages difficult to learn.
But, JavaScript does not come with strict rules and we can execute our code in the browser anyway but in some situations we can get unpredictable results which can be resolved once we understand the basics of the language.

3. Interpreted Language

Since JavaScript is the interpreted language, we can execute JavaScript code in any platform like Windows, Mac, and Linux.

4. Make Web Pages Interactive

As we use HTML to make a webpage and its structure and CSS to make the webpage more stylish (changing its fonts, colors, borders, margins, paddings), but to make a webpage interactive (handling user actions, events, making popup windows, changing of images), we use JavaScript.

5. Provides Rich Frameworks

JavaScript comes with rich set of frameworks like Angular.js, Node.js, Backbone.js, React.js, and Ember.js.
Each framework has its own purposes and uses.

Want to learn more about JavaScript frameworks, Click Here.

6. Visual Effects

JQuery (which is a library written in JavaScript) and Ajax (a framework of JavaScript) are used to make Web Page's UI (User Interface) by adding visual effects, animations, sliders, which give webpage a more graphical representations and make it user-friendly.

7. Server-Side Programming

Initially, JavaScript was used as front-end or client-side scripting language but now Node.js (which is the framework of JavaScript) is developed, which enables JavaScript to be used for server-side scripting.

Here's a good write up on Beginner's Guide To Node.js (Server-side JavaScript)

8. Used To Develop Hybrid (Mobile) Apps

JavaScript is also used for developing hybrid (mobile) apps using frameworks like PhoneGap and Ionic.

9. Used To Develop Video Games

JavaScript is also used for developing browser games.
There are several JavaScript frameworks developed for developing browser games like Phaser.js, Babylon.js, Pixi.js, MelonJs, and Kiwi.js.
Also, there are several game engines which use JavaScript for scripting like Unity3D and PlayCanvas to develop cross-platform video games.

10. Large Community

There is a large community of JavaScript programmers.
It has big support on several websites like Udemy, Coursera, CodeAcademy, edX, which provide forums and tutorials to help beginners in learning JavaScript easily.

Take Udemy course to learn JavaScript here.

11. Its Everywhere

JavaScript is everywhere.
It is used in Website UI design, backend (server-side scripting), hybrid and mobile applications development, and game development.
Once we learn JavaScript, we become a Full-Stack Developer.