HTML, CSS, and JavaScript are the three fundamental languages used in Front-End Development. These languages work together to create the user interface (UI) and enable interactivity on websites.

HTML (Hypertext Markup Language) is the backbone of any web page. It defines the structure and content of a webpage using various tags. For example, the <h1> tag represents a heading, while the <p> tag represents a paragraph.

CSS (Cascading Style Sheets) is responsible for the visual styling of a webpage. It controls the layout, colors, fonts, and other aesthetic aspects of the UI. Selectors, properties, and values are used in CSS to target HTML elements and apply specific styling.

JavaScript, often referred to as JS, is a powerful programming language that makes websites interactive. It allows you to add functionality and behavior to your web pages. With JavaScript, you can validate forms, create dynamic content, and handle user interactions.

To illustrate these concepts, let's consider a simple web page. The HTML would define the structure and content, while the CSS would handle the visual styling. JavaScript, on the other hand, could be used to display an alert message when a button is clicked or to validate a user's input in a form.

By combining these three languages, you can create visually appealing and interactive websites, engaging users and providing them with a seamless experience.