The sessionStorage object stores data for only one session. (The data is deleted when the browser is closed).

Does sessionStorage expire?

It doesn’t expire automatically. So if you never close your browser it never expires. So when the tab/window is closed the data is lost. Each sessionstorage area is allowed 5MB of storage (in some browsers 10MB).

Does localStorage last forever?

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.