A JavaScript developer’s guide to browser cookies

JavaScript developers can learn about browser cookies and their functionalities, including how they work, how to access and manipulate them from both client and server sides, and how to control their visibility using attributes. Cookies, small data pieces stored in browsers, are created during HTTP requests and are used for session management, personalization, and user behavior tracking. However, due to performance issues, modern web development favors Web Storage APIs for client-side storage. Cookies can be set and accessed via JavaScript on the client-side using the Document property or through server-side manipulation using request and response headers. Important cookie attributes include Domain, Path, Expires, Secure, HttpOnly, and SameSite, which control aspects such as security, accessibility, and lifespan. Concerns about third-party cookies tracking users across websites have led to browser features like enhanced tracking protection and state partitioning, while new APIs are under development to balance privacy with functionality.