What is the primary use for JavaScript in web development?

JavaScript is primarily used in web development to enhance interactivity and dynamic content. This means that JavaScript allows developers to create engaging user experiences by enabling elements on the page to respond to user actions, such as clicks, hovers, or form inputs. For example, JavaScript can be used to update content dynamically without needing to reload the entire page, create animations, validate user input in forms, and interact with APIs to fetch or send data. This interactivity significantly improves the overall user experience, making websites more responsive and appealing.

In contrast, the other options have distinct roles. Creating static web pages is typically the realm of HTML, which structures content but does not provide interactivity. Structuring content refers to defining the layout and organization of a webpage, which is primarily done with HTML. Providing styles to a webpage is the domain of CSS, which is responsible for the visual presentation and aesthetics of the site. JavaScript complements these technologies by adding the crucial layer of interactivity that is essential in modern web applications.