What is localStorage and sessionStorage? | HTML Interview Questions

What You'll Learn

Difference between localStorage and sessionStorage
How to use Web Storage API
When to use each

Web Storage API

Storage	Persistence
`localStorage`	Forever (until cleared)
`sessionStorage`	Until tab closes

Both store key-value pairs as strings with ~5-10MB limit.

localStorage Example

code.jsJavaScript

// Set items
localStorage.setItem('theme', 'dark');
localStorage.setItem('user', JSON.stringify({ name: 'John', id: 1 }));

// Get items
const theme = localStorage.getItem('theme'); // 'dark'
const user = JSON.parse(localStorage.getItem('user'));

// Remove items
localStorage.removeItem('theme');
localStorage.clear(); // remove all

sessionStorage Example

code.jsJavaScript

// Cleared when tab closes
sessionStorage.setItem('formDraft', 'unsaved content');
const draft = sessionStorage.getItem('formDraft');

Use Cases

localStorage: User preferences, cached data, app state
sessionStorage: Form drafts, temporary data, shopping cart

Important Note

Unlike cookies, storage data isn't sent to the server with every request.