Window.localStorage - Web APIs 编辑

The read-only localStorage property 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 data stored in localStorage has no expiration time, data stored in sessionStorage gets cleared when the page session ends — that is, when the page is closed. (Data in a localStorage object created in a "private browsing" or "incognito" session is cleared when the last "private" tab is closed.)

Data stored in either localStorage 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 localStorage object from the same site accessed with HTTPS (e.g., https://example.com).

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

Syntax

myStorage = window.localStorage;

Value

A Storage object which can be used to access the current origin's local storage space.

Exceptions

SecurityError

The request violates a policy decision, or the origin is not a valid scheme/host/port tuple (this can happen if the origin uses the file: or data: scheme, for example). For example, the user may have their browser configured to deny permission to persist data for the specified origin.

Example

The following snippet accesses the current domain's local Storage object and adds a data item to it using Storage.setItem().

localStorage.setItem('myCat', 'Tom');

The syntax for reading the localStorage item is as follows:

const cat = localStorage.getItem('myCat');

The syntax for removing the localStorage item is as follows:

localStorage.removeItem('myCat');

The syntax for removing all the localStorage items is as follows:

localStorage.clear();

Note: Please refer to the Using the Web Storage API article for a full example.

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• Using the Web Storage API
• Window.sessionStorage