Introduction

JavaScript powers the modern web. It lets you create interactive experiences, manipulate the DOM, and communicate with servers.

Variables

let name = "Alice";
const PI = 3.14159;
var old = true; // avoid var in modern code

Functions

function greet(person) {
  return `Hello, ${person}!`;
}
const add = (a, b) => a + b;

Asynchronous JavaScript

async function fetchData(url) {
  const response = await fetch(url);
  const data = await response.json();
  return data;
}

DOM Manipulation

document.getElementById('myBtn').addEventListener('click', () => {
  alert('Button clicked!');
});

Playground