A popular programming language used for web development is JavaScript. This versatile language is primarily employed for creating interactive and dynamic content on websites, enhancing user experience through responsive features. In conjunction with HTML and CSS, JavaScript allows developers to build user interfaces, validate forms, and manipulate the Document Object Model (DOM). Additionally, with the rise of frameworks like React and Node.js, JavaScript has expanded its capabilities to include server-side development, making it a foundational language in modern web development practices.