JavaScript Essentials

Introduction

JavaScript is the brain of the web. It allows you to build interactive UI, handle events, and connect to APIs seamlessly.

console.log("Welcome to Developer HUB!");

Variables & Data Types

• let – block-scoped variable (mutable)
• const – block-scoped variable (immutable)
• var – function-scoped variable (old style)

let name = "Muaaz";
const age = 18;
console.log(`${name} is ${age} years old.`);

Functions

Functions allow you to reuse logic and structure your code neatly.

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

console.log(greet("Developer")); // Output: Hello, Developer!

Loops & Conditionals

Control how your code runs and responds to data.

for (let i = 1; i <= 5; i++) {
  console.log(i);
}

if (true) {
  console.log("Condition is true!");
}

DOM Manipulation

Access and modify elements dynamically in the browser.

document.querySelector("h1").textContent = "Hello, JS World!";
document.body.style.background = "#0a192f";

Fetching APIs

Interact with external data using fetch() and promises.

fetch("https://api.github.com/users/codewithmuaaz")
  .then(res => res.json())
  .then(data => console.log(data))
  .catch(err => console.error("Error:", err));