sessionStoragedata

sessionStoragedata refers to the data stored in the Web Storage API’s sessionStorage object, a browser feature that allows web applications to save key‑value pairs on the client side for the lifespan of a single browser tab. When a user opens a new tab or window, the sessionStorage object is created empty; data is automatically discarded when that tab or window is closed or the browser is shut down. Unlike localStorage, sessionStorage data is not shared across tabs, windows, or sub‑domains, providing isolation between independent browsing contexts.

The API exposes simple methods: setItem(key, value) to store a value, getItem(key) to retrieve a value, removeItem(key) to delete a key, and clear() to wipe the entire storage. Keys and values are strings; non‑string values must be serialized, typically using JSON.stringify, before storage. The interface also provides length and key(index) to enumerate stored items, and a storage event that notifies other contexts when changes are made, though this event does not fire for the tab that performed the change.

sessionStorage is useful for preserving transient state such as form drafts, wizard steps, or UI preferences that should only persist while a user is actively interacting with a particular tab. It offers faster access than cookies and avoids network round‑trips, but it has a cumulative storage quota—generally around 5 to 10 megabytes per origin on modern browsers. The data is tied to the specific origin (scheme, host, and port) and cannot be accessed by other origins. Databases like IndexedDB can provide larger, more structured storage. Recommendations for using sessionStorage include treating it as volatile memory, handling JSON parsing errors gracefully, and avoiding storage of sensitive information unless encrypted or tied to a secure context.