Start by learning the basics. JavaScript is a programming language, so you'll need to learn the fundamentals of programming, such as data types, variables, loops, and functions.
https://www.w3schools.com/js/

Practice, practice, practice. The best way to learn any programming language is to practice writing code. Set aside dedicated time each day to write JavaScript code, and try to build simple programs or scripts to help you understand the concepts you're learning.
https://edabit.com/challenges/javascript

Find a good tutorial or book. There are many excellent tutorials and books available online that can help you learn JavaScript quickly. Look for tutorials that focus on the basics and provide plenty of code examples that you can follow along with.
https://amzn.to/3FbXdgL

Join online communities. There are many online communities, forums, and groups dedicated to JavaScript and programming. Joining these communities can be a great way to learn from experienced developers, ask questions, and get feedback on your code.
https://dev.to/t/javascript
https://hashnode.com/n/javascript

Use online resources. There are many online resources, such as videos, interactive courses, and code challenges, that can help you learn JavaScript quickly. These resources can be a great supplement to tutorials and books and can provide you with a more interactive and engaging learning experience.

Overall, the key to learning JavaScript quickly is to be dedicated and committed to practicing and learning regularly. By setting aside dedicated time to learn and using a variety of learning resources, you can quickly become proficient in JavaScript.