JavaScript is a versatile, high-level scripting language that is integral to web development, enabling interactive and dynamic content on websites. Initially developed by Netscape in 1995, it has since become a cornerstone of front-end development alongside HTML and CSS. JavaScript allows developers to create responsive user interfaces, handle events, validate forms, and perform asynchronous operations using techniques like AJAX. It runs on the client side in the browser, which helps reduce server load and enhance user experience. With the advent of frameworks and libraries such as React, Angular, and Vue.js, JavaScript’s capabilities have expanded significantly, enabling the development of complex single-page applications (SPAs) and improving code maintainability and efficiency. Additionally, with Node.js, JavaScript can also be used on the server side, making it a full-stack development language.