JavaScript (JS) is a programming language that is commonly used to create and control dynamic and interactive content on the web. JavaScript is a client-side language, which means that it is executed by the web browser on the user's computer, rather than on the web server. JavaScript is used to create and control a wide range of web content, including animations, games, apps, and other interactive elements. JavaScript is often used in conjunction with other technologies, such as HTML and CSS, to create and style web pages, and can be integrated with other web frameworks and libraries, such as React and Angular, to create more complex and powerful web applications. JavaScript is a popular and powerful language, and is supported by all modern web browsers.