sessionStorage property

Storage get sessionStorage

The read-only sessionStorage property accesses a session Storage object for the current . sessionStorage is similar to Window.localStorage; the difference is that while data in localStorage doesn't expire, data in sessionStorage is cleared when the page session ends.

• Whenever a document is loaded in a particular tab in the browser, a unique page session gets created and assigned to that particular tab. That page session is valid only for that particular tab.
• A page session lasts as long as the tab or the browser is open, and survives over page reloads and restores.
• Opening a page in a new tab or window creates a new session with the value of the top-level browsing context, which differs from how session cookies work.
• Opening multiple tabs/windows with the same URL creates sessionStorage for each tab/window.
• Duplicating a tab copies the tab's sessionStorage into the new tab.
• Closing a tab/window ends the session and clears objects in sessionStorage.

Data stored in sessionStorage is specific to the protocol of the page. In particular, data stored by a script on a site accessed with HTTP (e.g., http://example.com) is put in a different sessionStorage object from the same site accessed with HTTPS (e.g., example.com).

The keys and the values are always in the UTF-16 string format, which uses two bytes per character. As with objects, integer keys are automatically converted to strings.

Implementation

external Storage get sessionStorage;