Which technology primarily enables client-side interactivity on websites?

JavaScript is the primary technology that enables client-side interactivity on websites. It allows developers to create dynamic and interactive user interfaces by manipulating HTML content in response to user actions, such as clicks, mouse movements, and keyboard input. Through JavaScript, web developers can enhance the user experience by updating portions of a webpage without requiring a complete page reload, making applications feel more responsive and fluid.

JavaScript also supports various libraries and frameworks that streamline the process of building interactive components, such as form validation, animations, and real-time updates. This versatility makes it an essential tool in modern web development, allowing for rich, interactive user experiences that are crucial in today's web applications.

The other technologies listed serve different purposes. Cascading Style Sheets are primarily used for styling and layout, determining how HTML elements appear visually but not providing the interactive functionality that JavaScript does. HTML is the foundational markup language for creating the structure of web pages but lacks the capability for dynamic interaction on its own. AJAX, which stands for Asynchronous JavaScript and XML, is used to send and retrieve data asynchronously from a server, allowing parts of a webpage to update without reloading the entire page. While AJAX relies on JavaScript to work, it is more of a technique for making