AngularJS

AngularJS is a structural, open-source JavaScript framework for building dynamic web applications. It was initiated by Google and released in 2010 to simplify client-side scripting and enable richer browser-based apps. AngularJS extends HTML with declarative templates and supports two-way data binding between the model and the view, reducing the amount of boilerplate code developers must write.

Key concepts include directives, which extend HTML with new attributes and elements; models and views bound by two-way data binding; dependency injection to modularize components; and a modular architecture based on units called modules that group related code. The framework emphasizes testability and provides support for unit and end-to-end testing.

In AngularJS, the view is controlled by controllers and coordinated with the scope object, which exposes data and behavior to templates. The digest cycle runs to detect changes and update the DOM. Directives may manipulate the DOM, create reusable components, or implement custom UI behavior. Routing can be added via the ngRoute module or through third-party libraries such as ui-router.

Historically, AngularJS achieved widespread use for single-page applications and established a distinct identity from later Angular versions, which began as a complete rewrite designed around components and TypeScript. AngularJS reached end of life on December 31, 2021, with Google signaling that long-term support would end and migration to modern Angular would be preferred for new work.

Today, AngularJS remains in maintenance for legacy projects, but most new development has moved to Angular or other contemporary frameworks due to ongoing updates, performance considerations, and a more active ecosystem.