JavaScript is a versatile programming language used to create dynamic and interactive content on websites. It runs in the browser and can manipulate HTML and CSS, making webpages responsive to user actions.

Although they share a similar name, Java and JavaScript are distinct languages. Java is a full-fledged programming language used primarily for server-side and application development, while JavaScript is mainly for web development and runs in the browser.

The Document Object Model (DOM) represents the structure of an HTML document. JavaScript can interact with the DOM to dynamically change the content and structure of a webpage. Elements of the DOM can be accessed and manipulated using JavaScript.