Echo is an open-source framework for developing rich web applications. From the developer's perspective, Echo behaves as a user interface toolkit--like Swing or Eclipse SWT. AJAX technology is employed to deliver a user experience to web clients that approaches that of desktop-based applications. Echo applications can be created entirely in server-side Java code using a component-oriented and event-driven API (applies to Echo2 and Echo3) or as client-side applications written in JavaScript (applies to Echo3 only). Echo2 is the current stable release of the Echo platform.

Echo3 is the next generation of the Echo platform. Echo3 features the ability to create applications in either client-side JavaScript or in server-side Java. It offers superior performance to Echo2, and a substantially easier API for creating custom AJAX components that will use custom HTML and JavaScript.


The YUI Library is fully documented on its website; detailed API documentation accompanies the library download. It has six types of components: YUI core, utilities, UI controls, CSS components, developer tools, and build tools.

Source: Echo