Richie Rich is an HTML document editor that runs within a Web browser. Unlike other in-line HTML editors, this operates straight on the DOM to avoid incongruities between what is visible in the front end and the HTML that is created in the back end. It supports undo, mouse selection, cursor positioning, and creation of headings, paragraphs, lists, links, bold, italic, and underline.
openWYSIWYG is a cross-browser WYSIWYG editor packed with every rich-text editing feature you need to make your content management system or custom Web application that much better. It easy easy to set up, and you can quickly turn any text area into a powerful WYSIWYG editor with just a few simple lines of code.
SynchroEdit is a browser-based document editor for use by multiple users simultaneously. It is a form of same-time, different-place groupware. It allows multiple users to edit a single web-based document at the same time, and it continuously synchronizes all changes so that users always have the same version.
Xinha is a cross browser, cross platform Embedded WYSIWYG HTML Editor. Although it was originally a stop-gap version of the htmlArea Version 3.0rc1 editor during a period of inactivity in that project, it is now a fully fledged fork. Xinha includes a number of bugfixes and many enhancements over htmlArea, and is in active development by a small and growing number of developers.