What is JavaScript commonly used for in web development?

JavaScript is primarily known for enhancing interactivity and creating online programs in web development. It allows developers to implement dynamic features on web pages that improve user experience. For instance, JavaScript can be used to create interactive elements like sliders, forms that validate input in real-time, animations, and responsive navigation menus.

The language runs in the browser, enabling developers to manipulate HTML and CSS to update content dynamically without needing to reload the page. This capability is crucial for building engaging user interfaces and single-page applications (SPAs) where content can change based on user actions in a seamless manner.

While other options mention important aspects of web development, they do not accurately represent the primary role of JavaScript. Server-side applications are typically built with languages like Node.js, HTML structures content on the web page, and database management usually involves server-side languages or frameworks. JavaScript's strength lies in enhancing the client's experience directly in the browser.