JavaScript is an object-oriented scripting language used to enable programmatic access to objects within both the client application and other applications. It is primarily used in the form of client-side JavaScript, implemented as an integrated component of the web browser, allowing the development of enhanced user interfaces and dynamic websites. JavaScript is a dialect of the ECMAScript standard and is characterized as a dynamic, weakly typed, prototype-based language with first-class functions. JavaScript was influenced by many languages and was designed to look like Java, but to be easier for non-programmers to work with.
JavaScript is a versatile language. It can be used to create menus, validate forms, provide interactive calendars, post the current day's headlines, produce background effects on a Web page, track a visitor's history on your site, and play games, among many other things. That's probably why it's one of the most popular languages on the World Wide Web.