What is a cookie in web development?

In web development, a cookie is a small piece of text data that is stored by a user's web browser. This data is created when a user visits a website and can include information such as user preferences, session identifiers, and other data that the website wants to remember between sessions. Cookies enable websites to offer a more personalized experience by keeping track of users' activities and providing contextual information that enhances usability.

Cookies can be set with specific attributes such as expiration dates, domain restrictions, and path scopes to control their behavior, which plays a crucial role in sessions, authentication, and tracking user interactions. The role of cookies is fundamental in maintaining state in stateless web protocols like HTTP, allowing developers to deliver dynamic, user-centric experiences.

Other options such as a JavaScript function, an image file, or script code for server-side processing do not encapsulate the concept of cookies in web development, as they refer to entirely different elements and functionalities within web applications.