Which programming language is primarily used for front-end development?

JavaScript is primarily used for front-end development due to its ability to create interactive and dynamic web pages. This programming language runs in the browser, allowing developers to manipulate the Document Object Model (DOM) of a webpage, respond to user events, and communicate asynchronously with servers.

The web's visual elements and user interface behaviors heavily rely on JavaScript, making it essential for creating responsive and engaging experiences on the client side. While other languages like Python and Ruby are often used for back-end development, where server-side processing and data management take place, they are not typically utilized for front-end tasks. C#, while powerful, is mainly associated with server-side development, particularly within the context of ASP.NET frameworks for web applications. Thus, JavaScript stands out as the primary language for developing client-side features in modern web applications.