localStorage vs sessionStorage in JavaScript

In web development, localStorage and sessionStorage are two commonly used mechanisms for storing data on the client side. They are part of the Web Storage API and allow developers to store key-value pairs in a web browser, but they serve different purposes. Let's dive into the differences through a comparison table and a concrete example.

'localStorage' vs 'sessionStorage' in JavaScript


localStorage is used to store data with no expiration time, meaning the data will persist even after the browser is closed and reopened. It's useful for storing preferences or other data that doesn't need to be transmitted to the server with every request.


sessionStorage, on the other hand, stores data only for a session's duration. Once the browser tab or window is closed, the stored data will be deleted. It's great for storing temporary data, like information related to the current session.

Comparison Table

Feature 'localStorage' 'sessionStorage'
Lifespan Persistent (no expiration) Limited to session duration
Storage Limit Usually around 5MB per domain Usually around 5MB per domain
Accessibility Across tabs and windows Limited to the same tab or window
Storage Context Shared across sessions Isolated to a single session

Example with Explanation

Here's an example to illustrate how both storage mechanisms work:

Using 'localStorage'
// Storing a value in localStorage
localStorage.setItem('username', 'Alice');

// Retrieving the value even after browser restart
console.log(localStorage.getItem('username')); // Outputs 'Alice'
With localStorage, the stored data will remain even if the browser is closed and reopened later.

Using 'sessionStorage'
// Storing a value in sessionStorage
sessionStorage.setItem('cartItem', 'Laptop');

// Retrieving the value within the same session
console.log(sessionStorage.getItem('cartItem')); // Outputs 'Laptop'

// The value will be lost if the browser tab or window is closed
With sessionStorage, the stored data will only be accessible during the current browser session and will be lost if the tab or window is closed.


Both localStorage and sessionStorage provide useful ways to store client-side data, but their use cases are different based on the persistence and scope of the storage.
  • Use localStorage when you need to store data across browser sessions and tabs.
  • Use sessionStorage when you want to store data that are specific to a single session or tab.
Understanding the differences between these two storage mechanisms will help you choose the right tool for your specific needs, enhancing both the performance and user experience of your web applications.