This is my JS notes

Author : AKASH HALDER

As we all know that JavaScript is a versatile programming language commonly used to enhance interactivity in web browsers. It enables developers to create dynamic and engaging user interfaces.

1.Frontend:

In frontend development, JavaScript is primarily used to make web pages dynamic. It allows for real-time updates, interactive forms, and responsive user experiences. Frameworks like React, Angular, and Vue use JavaScript to build powerful frontend applications.

2.Backend:

On the backend, JavaScript (with Node.js) is employed to handle server-side logic. It facilitates the creation of scalable and efficient server applications. With Node.js, JavaScript can manage server tasks, handle requests, and interact with databases, providing a full-stack development capability.

In This you will Find all the required essential knowledge for making Good Website => 1. FrontEnd 2.BackEnd(Kick start = async JS) | Here,I have focused more on frontend than backend.

Here I have Included some Projects So that others can actually understand the application of Javscript in FrontEnd

1. Learn the essential basics of Javascript
2. Master some Advance Javscript Topics
3. Apply your knowledge into some useful frontend Projects

JavaScript Topics Overview

Welcome to this comprehensive guide on essential JavaScript topics. Below, you'll find a brief explanation of each topic along with a code example to help you grasp the concepts quickly.

Table of Contents

1. [Variables and Data Types](#1-variables-and-data-types) 2. [Control Flow](#2-control-flow) 3. [Functions](#3-functions) 4. [Arrays](#4-arrays) 5. [Objects](#5-objects) 6. [Loops](#6-loops) 7. [Conditions](#7-conditions) 8. [Promises](#8-promises) 9. [Async/Await](#9-asyncawait) 10. [Event Handling](#10-event-handling) 11. [DOM Manipulation](#11-dom-manipulation)

1. Variables and Data Types

JavaScript is dynamically typed, and variables can be declared using var, let, or const. Data types include numbers, strings, booleans, objects, arrays, and null.

let name = "John";
let age = 25;
let isStudent = true;
const PI = 3.14;

2. Control Flow

Control flow statements include if, else if, else, switch, and the ternary operator (? :), enabling you to make decisions in your code.

let grade = 75;

if (grade >= 90) {
  console.log("A");
} else if (grade >= 80) {
  console.log("B");
} else {
  console.log("C");
}

3. Functions

Functions in JavaScript can be defined using the function keyword. Arrow functions provide a concise syntax.

function greet(name) {
  return `Hello, ${name}!`;
}

const add = (a, b) => a + b;

4. Arrays

Arrays store multiple values. You can access, modify, and manipulate arrays using various methods.

let colors = ["red", "green", "blue"];
colors.push("yellow");
console.log(colors[2]); // Output: blue

5. Objects

Objects represent key-value pairs and are widely used in JavaScript.

let person = {
  name: "Alice",
  age: 30,
  isStudent: false,
};
console.log(person.name); // Output: Alice

6. Loops

JavaScript supports for, while, and do-while loops for iterative tasks.

for (let i = 0; i < 5; i++) {
  console.log(i);
}

7. Conditions

Ternary operators and logical operators (&&, ||, !) help in handling conditions effectively.

let isLoggedIn = true;
let message = isLoggedIn ? "Welcome back!" : "Please log in.";

8. Promises

Promises are used for asynchronous programming, representing the eventual completion or failure of an asynchronous operation.

const fetchData = new Promise((resolve, reject) => {
  // Async operation
  if (success) {
    resolve(data);
  } else {
    reject(error);
  }
});

9. Async/Await

Async/await simplifies asynchronous code, making it more readable and easier to work with promises.

async function fetchData() {
  try {
    let response = await fetch('https://api.example.com/data');
    let data = await response.json();
    console.log(data);
  } catch (error) {
    console.error('Error fetching data:', error);
  }
}

10. Event Handling

JavaScript handles events triggered by user actions. Common events include click, keyup, and submit.

document.getElementById("myButton").addEventListener("click", function() {
  alert("Button clicked!");
});

11. DOM Manipulation

The Document Object Model (DOM) allows you to manipulate the structure, style, and content of HTML documents.

document.getElementById("myElement").innerHTML = "New content";

Feel free to explore each topic in-depth and use the provided examples as a starting point for your JavaScript journey. Happy coding!