What is JavaScript?

JavaScript is a client-side technology that enables interactivity on web pages, allowing developers to create dynamic and engaging user experiences. By utilizing JavaScript, developers can manipulate HTML elements, respond to user actions, validate forms, and create AJAX requests to exchange data with the server asynchronously without requiring a page reload. This enhances the overall usability and responsiveness of web applications.

In the context of web development, JavaScript is often implemented alongside HTML and CSS, forming the three core technologies that drive the creation of interactive websites. Unlike server-side technologies, which manage application logic, database interactions, or server responses, JavaScript runs directly in the user's web browser, making it essential for tasks that require immediate feedback or user interaction.

The other options presented focus on different technologies or functions. A markup tag refers to elements of HTML or XML that control the structure or presentation of content rather than providing interactivity. Server-side technology for running Java applications pertains to a different programming language, Java, which is typically used for backend processing rather than client-side interactivity. A database management system is a technology for storing and managing data instead of facilitating interaction on web pages.