Which storage API stores data as key-value pairs with no expiration by default and persists across sessions?

Which storage API stores data as key-value pairs with no expiration by default and persists across sessions?

• A. SessionStorage
• B. AppCache
• C. Geolocation API
• D. LocalStorage

Answer: (D)

LocalStorage is the web storage API that stores information as simple key-value pairs on the client, with no built-in expiration. Because there’s no automatic timeout, items stay there until you explicitly remove them, and they persist across browser restarts, so the data remains available in future sessions. It’s scoped to the origin, meaning data saved on a site isn’t accessible to other sites. Values are stored as strings, so to save objects you typically serialize with JSON.stringify and parse with JSON.parse when reading. For example, setItem stores a value, getItem retrieves it, and removeItem or clear deletes it. This behavior matches the requirement of key-value storage that persists across sessions without a default expiration. In contrast, sessionStorage is limited to a single session and clears when the tab or browser is closed, AppCache is a deprecated offline caching mechanism, and the Geolocation API is unrelated to storage.

LocalStorage is the web storage API that stores information as simple key-value pairs on the client, with no built-in expiration. Because there’s no automatic timeout, items stay there until you explicitly remove them, and they persist across browser restarts, so the data remains available in future sessions. It’s scoped to the origin, meaning data saved on a site isn’t accessible to other sites. Values are stored as strings, so to save objects you typically serialize with JSON.stringify and parse with JSON.parse when reading. For example, setItem stores a value, getItem retrieves it, and removeItem or clear deletes it. This behavior matches the requirement of key-value storage that persists across sessions without a default expiration. In contrast, sessionStorage is limited to a single session and clears when the tab or browser is closed, AppCache is a deprecated offline caching mechanism, and the Geolocation API is unrelated to storage.