My Java Full Stack learning journey : JavaScript

Hi everyone !

Introduction to JavaScript

1. what is JavaScript?
JavaScript is a high-level,** interpreted programming language** used to make web pages interactive and dynamic.
While HTML structures a web page and CSS styles it, JavaScript adds behavior.
JavaScript runs inside the browser, which means it doesn’t need to be installed separately for users—it just works.

2.Who Invented JavaScript?
JavaScript was invented in 1995 by Brendan Eich, a programmer working at Netscape Communications.
He developed the first version of JavaScript in just 10 days! It was initially called Mocha, then renamed LiveScript, and finally became JavaScript.

JavaScript Versions :

• ES1-1997-First edition
• ES3-1999-Regular expressions, try/catch
• ES5-2009-Strict mode, JSON support
• ES6-(ES2015)-2015-let/const, arrow functions, classes, promises
• ES7 - ES14-2016–2023-Async/await, optional chaining, nullish coalescing, top-level await, etc.

3.What is the Current Version of JavaScript?
The latest version as of** 2025 is ECMAScript 2024 (ES15), which was released in **June 2024.

It includes improvements like:

• Set methods (like union, intersection)
• Array grouping
• New decorators syntax
• Performance optimizations

JavaScript evolves every year, and each version adds useful tools for modern web development.

JavaScript Data Types:
1. Primitive Data Types (store single values):

• String – e.g., "Hello"
• Number – e.g., 10, 3.14
• Boolean – e.g., true, false
• Undefined – a variable declared but not assigned
• Null – represents an empty or unknown value
• BigInt – for very large numbers
• Symbol – unique identifiers

2. Non-Primitive (Reference) Data Types:

• Object – key-value pairs
• Array – list of values
• Function – reusable blocks of code

4.What are Variables in JavaScript?
A variable is like a container that stores data.
In JavaScript, you can declare variables using:

• var – old way, function-scoped -** let **– block-scoped, modern usage
• const – block-scoped, but value cannot be reassigned

Final thoughts:
JavaScript is the backbone of modern web development, powering everything from simple websites to full-scale web applications. Knowing its history, versions, data types, and variables is the first step toward becoming a skilled developer.

Stay curious and keep coding!