What is LOCAL STORAGE and How to use it

The localStorage read-only property of the window interface allows you to access a Storage object for the Document's origin; the stored data is saved across browser sessions.
localStorage is similar to sessionStorage, except that while localStorage data has no expiration time, sessionStorage data gets cleared when the page session ends - that is when the page is closed. (localStorage data for a document loaded in a "private browsing" or "incognito" session is cleared when the last "private" tab is closed.)