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

SecurityError

Thrown in one of the following cases:

• The origin is nota valid scheme/host/port tuple. This can happen if the origin uses thefile: ordata: schemes, for example.
• The request violates a policy decision. For example, the user has configured the browsers to prevent the page from persisting data.

Note that if the user blocks cookies, browsers will probably interpret this as an instruction to prevent the page from persisting data.

The keys and the values stored withlocalStorage are in theUTF-16 string format. As with objects, integer keys are automatically converted to strings.

localStorage datais specific to the protocol of the document. In particular, for a site loaded over HTTP (e.g.,http://example.com),localStorage returns a different object thanlocalStorage for the corresponding site loaded over HTTPS (e.g.,https://example.com).

For documents loaded fromfile: URLs (that is, files opened in the browser directly from the user's local filesystem, rather than being served from a web server) the requirements forlocalStorage behavior are undefined and may vary among different browsers.

In all current browsers,localStorage seems to return a different object for eachfile: URL. In other words, eachfile: URL seems to have its own unique local-storage area. But there are no guarantees about that behavior, so you shouldn't rely on it because, as mentioned above, the requirements forfile: URLs remain undefined. So it's possible that browsers may change theirfile: URL handling forlocalStorage at any time. In fact some browsershave changed their handling for it over time.

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

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

The syntax for reading thelocalStorage item is as follows:

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

The syntax for removing thelocalStorage item is as follows:

localStorage.removeItem("myCat");

The syntax for removing all thelocalStorage items is as follows:

localStorage.clear();

• Using the Web Storage API
• Window.sessionStorage