The setItem() method of the Storage interface, when passed a key name and value, will add that key to the storage, or update that key's value if it already exists.
The WindowEventHandlers.onstorage property contains an event handler that runs when the storage event fires. This occurs when a storage area is changed (e.g. a new item is stored.)
The Storage interface of the Web Storage API provides access to the session storage or local storage for a particular domain, allowing you to for example add, modify or delete stored data items.
The key() method of the Storage interface, when passed a number n, returns the name of the nth key in the storage. The order of keys is user-agent defined, so you should not rely on it.
Storage objects are simple key-value stores, similar to objects, but they stay intact through page loads. The keys and the values are always strings (note that integer keys will be automatically converted to strings, just like what object do). You can access these values like an object, or with the getItem() and setItem() methods. These three lines all set the colorSetting entry in the same way:
The localStorage property allows you to access a local Storage object. localStorage is similar to sessionStorage. The only difference is that, while data stored in localStorage has no expiration time, data stored in sessionStorage gets cleared when the browsing session ends—that is, when the browser is closed.