Qt is a comprehensive, object-oriented development framework that enables development of high-performance, cross-platform rich-client and server-side applications. When you implement a program with Qt, you can run it on the X Window System (Unix/X11), Apple Mac OS X, and Microsoft Windows NT/9x/2000/XP by simply compiling the source code for the platform you want. Qt is the basis for the KDE desktop environment, and is also used in numerous commercial applications such as Google Earth, Skype for Linux, and Adobe Photoshop Elements.
WebGUI is a content management framework built to allow average business users to build and maintain complex Web sites. It is modular, pluggable, and platform independent. It was designed to allow the people who create the content to manage it online, rather than content management taking up the time of busy IT staff. WebGUI comes with a full host of features including shopping cart, subscriptions, forums, photo galleries, FAQs, link lists, blogs, SQL reports, a Web services interface, and a very configurable user privilege and profiling system.
phpHtmlLib is an application development framework for developing OOP style Web applications in PHP. The application framework supports an MVC style architecture and Ajaxable and Cacheable interfaces for developing rich client Web applications. It comtains a set of PHP classes and library functions to help facilitate building, debugging, and rendering of XML, HTML, XHTML, WAP/WML Documents, and SVG (Scalable Vector Graphics) images as well as complex HTML widgets.
BOND (building object network databases) is database development framework for rapidly creating applications. It creates live forms for the Web with AJAX and desktop applications using GTK. Using XML to define widget layouts, it drives the live forms to which SQL statements and methods can be attached.
The Zero Memory Widget library is as powerful as classic widget libraries, but it does not use a single bit of memory per widget. So with this library, there is no widget pointer/reference, instance creation/destruction, event handler function, functions to read/write data between widget and application, and so on. GUI programming with this library is done in the C language, and it is as easy as composing an HTML page.
Luxor is an open-source XML User Interface Language (XUL) toolkit in Java that lets you build UIs using XML and also includes an ultra light-weight, multi-threaded Web server, a portal engine, and a template engine. It is also Web Start-ready, as everything fits in a jar and requires no loose files.