a - JavaScript Introduction JavaScript is a versatile interpreted programming language. It was primarily used to add interactivity and dynamic behavior to web pages It runs on web browsers as well as on servers using Node.js You can also create desktop applications using Electron Using React Native, Ionic and other frameworks and libraries you can create mobile application for Android and iOS JS is one of the core technologies of the World Wide Web along with HTML and CSS JS originally designed by Brendan Eich at Netscape in 1995
b - Javascipt Key Features Interactivity → JS allows developers to create interactive web pages that change on user actions Client-Side execution → Running on the client-side(web browsers), reduces the server load Rich Web Applications → It supports complex applications through frameworks (React, Angular, and Vue.js) building single-page applications (SPAs) Cross-Platform Compatibility → While primarily used on browsers, JavaScript can also run in other environments such as Node.js for server-side programming, IoT devices, and more. Event-Driven Programming → JavaScript uses an event-driven model to respond to events triggered by the user or browser actions like mouse clicks, key presses, etc. Rich API → It provides a vast array of built-in functions (APIs) for tasks ranging from manipulating images and videos in real time to accessing hardware features directly through browsers. Dynamic Typing → JavaScript is dynamically typed, which means that variable types are not defined until the code is run and can change during execution. Popularity → It's widely used due to its simplicity and flexibility, making it a cornerstone for both front-end (client-side) and back-end development (using Node.js).
c - JavaScript Versions 1/2 ES1 → ECMAScript 1 → 1997 → First release ES2 → ECMAScript 2 → 1998 → Minor changes ES3 → ECMAScript 3 → 1999 → regular expressions, do-while, switch, try/catch ES4 → ECMAScript 4 → Never Released. ES5 → ECMAScript 5 → 2009 → JavaScript strict mode, Multiline strings, String.trim(), Array methods, Object methods, Getters and setters, Trailing commas ES6 → ECMAScript 2015 → 2015 → let and const statements, Map and set objects, Arrow functions, For/of loop, Some array methods, Symbol, Classes, Promises, JavaScript Modules, New Number methods and properties, For/of loop, Spread operator ES7 → ECMAScript 2016 → 2016 → Exponential (**) operator, Array.includes() method ES8 → ECMAScript 2017 → 2017 → Async/await, Object.entries() method, Object.values() method, Object.getOwnPropertyDescriptor() method, string padding
d - JavaScript Versions 2/2 ES9 → ECMAScript 2018 → 2018 → Rest object properties, JavaScript shared memory, Promise.finally() method, New features of the RegExp() object ES10 → ECMAScript 2019 → 2019 → String trim.start(), String trim.end(), Array.flat(), Revised Array.sort(), Revised JSON.stringify() / toString(), Object.fromEntries() method ES11 → ECMAScript 2020 → 2020 → Nullish Coalescing Operator (??), BigInt primitive data type ES12 → ECMAScript 2021 → 2021 → String.replaceAll() method, Promise.Any() method ES13 → ECMAScript 2022 → 2022 → static block inside the class, New class features, Top-level await ES14 → ECMAScript 2023 → 2023 → Array findLast() & findLastIndex(), Hashbang Grammer, Symbols as WeakMap keys