What are the differences between localStorage, sessionStorage, and cookies?

What are the differences between localStorage, sessionStorage, and cookies?

LocalStorage and SessionStorage are part of the Web Storage API, while cookies are a different mechanism for storing data. LocalStorage persists data even after the browser is closed, while SessionStorage only lasts for the duration of the page session. Cookies can be set to expire and are sent with every HTTP request, which can affect performance.

Can you give me examples of when to use each one?

Sure! Use localStorage for storing user preferences that should persist across sessions, sessionStorage for temporary data like form inputs during a single session, and cookies for server-side sessions or tracking user behavior.

What are the storage limits for each?

LocalStorage and SessionStorage typically have a limit of about 5-10MB per origin, while cookies are limited to about 4KB per cookie.

Are there any security concerns I should be aware of?

Yes, localStorage and sessionStorage are vulnerable to XSS attacks, so avoid storing sensitive information. Cookies can be secured with flags like HttpOnly and Secure.