sessionStoragesetItembrukerOla

sessionStorage is a web storage object defined by the HTML5 Web Storage API that allows web applications to store key/value pairs in a browser. The data stored in sessionStorage is tied to a specific browsing session, meaning it survives page reloads or navigation within the same tab but is cleared when the tab is closed or the browser is restarted. This makes sessionStorage suitable for storing temporary state such as user progress in a multi‑step form or client‑side cache that should not persist beyond the current user session.

The storage capacity of sessionStorage is similar to that of localStorage, typically around 5 to 10 megabytes per origin, though this varies by browser. Data is stored as strings; non‑string values must be stringified (e.g., JSON.stringify) before storage and parsed upon retrieval. Common methods include setItem(key, value), getItem(key), removeItem(key), and clear(), along with key(index) to enumerate stored keys. Developers often wrap these methods to provide type conversion and error handling.

Unlike localStorage, which retains data indefinitely until explicitly cleared, sessionStorage is cleared automatically when the browsing context ends. This difference is critical for security‑sensitive data that should not be left on the client after the session ends. Both storage types are accessible only to pages from the same origin, preventing cross‑site read or write access. However, neither storage mechanism provides encryption; sensitive data should be gated through secure channels or client‑side encryption. Browser support for sessionStorage is widespread across modern desktop and mobile browsers, making it a reliable choice for short‑lived client‑side persistence.