JavaScript is a programming language that is widely used for creating interactive and dynamic web content. It is a client-side scripting language, which means that it is executed in the user's web browser rather than on the server that hosts the website. JavaScript is used to add interactivity and functionality to web pages, such as form validation, dynamic menus, pop-up windows and animations. It can also be used to communicate with web servers and databases, enabling more complex web applications. JavaScript is supported by all modern web browsers and can be easily integrated with other web technologies, such as HTML and CSS.