Introduction to several major popular frameworks for Ajax

ExtJS ExtJS (Yui-ext) is a group of extensions from Yahoo! UI, a CS-style Web user interface component. The main UI includes: Dialog,grid,layout,tabs and so on.

jquery jquery is a fast, concise JavaScript toolbox that lets you manipulate HTML elements in a simple way, handle events, implement special effects, and add Ajax interactions to Web pages. jquery is designed to change the way you write JavaScript. Development tools: Aptana IDE

YUI Yahoo! User Interface Library (Yahoo! User Interface Library,yui) provides some tools and UI controls that are often used in developing web fat clients. Tools: Drag-and-drop (Drag Anddrop) operations, Connection Manager (XMLHttpRequest), page effects, browser events (such as mouse clicks and keyboard keys) management. UI controls: Automatic completion (autocomple), calendars (calendar), container (Container) class controls include hints (Tooltip), Panels (Panel), dialog boxes (Dialog), Menus (menu), Tabview, Treeview,logger.
Yui also included in the creation of a concise, flexible layout and can be compatible with a variety of browsers required CSS resources. Development tools: Aptana IDE

The Eclipse rap Eclipse Rap Project is designed to allow developers to leverage the Eclipse development model to build rich,ajax-enabled Web applications. It mainly utilizes the well-known Eclipse platform extension Point plug-in mechanism and a widget toolkit containing the Swt/jface API.

MYGWT is an open source Google Web Toolkit user Interface component library. It implements the ExtJS component entirely in GWT.
However, the project seems to have stopped and is no longer maintained, so it is not recommended.

Gwt-ext is a Web Interface component library based on GWT and ExtJS development. Components include: Grid with sorting, paging, and filtering capabilities, support for drag-and-drop operations, Comboboxe, Tab Panels, Menus&toolbars, Dialogs, forms, and so on.
It is said Gwt-ext not open source many things do not need their own handwriting (Gwtplugin to charge)

The Query UI is a set of UI controls and mouse interactions based on jquery to build a skin replacement feature. Used to help developers build Web applications with a good user experience. Interactive components include drag/dropping, sorting, selecting, and resizing. The UI controls built on these core interactions are: accordion, date picker, dialog, slider, table Sorter, and tab.

DWR (Direct Web Remoting) is a Web remote call framework. Leveraging this framework makes it easy to develop Ajax. Using DWR, you can invoke the service directly from the client using JavaScript -side Java method and returns a value to JavaScript as if it were a direct local client invocation (DWR dynamically generates JAVASCRIP code based on Java classes). Its latest version DWR0.6 add many features such as: Support for DOM trees automatic configuration, support spring (JavaScript remote invoke Spring bean), better browser support, and an optional commons-logging journaling operation.

Google Web Toolkit (GWT) is a Java Software development framework for developing AJAX applications similar to Google Maps and Gmail. GWT's design references Java AWT package design, class naming rules, interface design, event monitoring, and so on. You can use the Java programming language to develop your interface, and then use the GWT compiler to convert Java classes into JavaScript and HTML for browser execution. Eclipse Development Plug-in Googlipse.
Google publishes Google Web Toolkit. Google Web Toolkit is an open version of the Ajax Framework through which users can build Web applications such as Google Maps and Gmail. This Google Web Toolkit beta is free and it is a based on JavaTools and can work with any Java development tools.

GWT has been added to Google's code base, which contains a lot of APIs and development tools. Google product manager Bret Taylor says the GWT compiler simply converts a user's Java application into browser-supported JavaScript and HTML when the user deploys the application to the product.