Browser tab, javascripte, and sessionstoage

 Some note about browser tabs, javascript and session storage:

1. On same browser window, each tab will create and have its own session storage, the data stored in session storage are not shared between tabs. To share the data, use localstorage.

2. Data in session storage are kept as long as the tab is not closed. If user navigates away from current url to other urls, and then navigates back to the original url later, the previous session storage data are still available. Session storage will only lose if user closes the tab.

3. When the browser window is not active, or the tab is not the active, the javascript still still runs in background, although the event are raised slowly than active window or tab, (about once per second).