Cookies are files, often including unique identifiers, that are sent by web servers to web browsers, and which may then be sent back to the server each time the browser requests a page from the server.
Cookies can be used by web servers to identity and track users as they navigate different pages on a website, and to identify users returning to a website.
Cookies may be either “persistent” cookies or “session” cookies. A persistent cookie consists of a text file sent by a web server to a web browser, which will be stored by the browser and will remain valid until its set expiry date (unless deleted by the user before the expiry date). A session cookie, on the other hand, will expire at the end of the user session, when the web browser is closed.