The Web Storage API in JavaScript provides simple key–value storage in the browser. It comes in two main types:

? 1. localStorage

• Stores data with no expiration.

• Data persists even after the browser is closed.

? 2. sessionStorage

• Stores data for one session.

• Data is cleared when the tab/window is closed.

? Basic Usage Examples

? Set an item

localStorage.setItem('username', 'John');sessionStorage.setItem('theme', 'dark');

? Get an item

const user = localStorage.getItem('username'); // "John"

? Remove an item

localStorage.removeItem('username');

? Clear all storage

localStorage.clear();sessionStorage.clear();

? Example: Storing and Retrieving Data

// Save datalocalStorage.setItem("isLoggedIn", "true");// Read dataif (localStorage.getItem("isLoggedIn") === "true") {  console.log("User is logged in");}

? Storing Objects (use JSON)

const user = { name: "Alice", age: 30 };// StorelocalStorage.setItem("user", JSON.stringify(user));// Retrieveconst storedUser = JSON.parse(localStorage.getItem("user"));console.log(storedUser.name); // "Alice"

?? Notes

• Storage is per origin (protocol + domain + port).

• localStorage typically supports 5–10MB per origin.

• Avoid storing sensitive data (it's not secure).

• Works only in the browser, not in Node.js.

Let me know if you want a practical example (e.g., storing user preferences or cart data)!