AngularJS is an open-source JavaScript framework maintained by Google that was developed in 2009. It allows for the creation of browser-based applications with MVC functionality using client-side JavaScript. AngularJS aims to simplify development by allowing HTML elements to declaratively specify their logic and functions, reducing the need for JavaScript code. Key features include two-way data binding, directives to add new HTML elements and attributes, filters, and controllers to manage the view and application scope.