Inmedius DITA Storm is a web-based editor for the DITA XML format. It is entirely implemented in JavaScript making it easily embeddable in any web application. No browser plugin installation or server side script deployment is required.
In addition to being portable, it provides the ability to edit content in WYSIWYG mode, which makes it convenient for any DITA-unaware content editor. Working with the editor is as simple as with any text processor. DITA Strom has full awareness of editing context and limits editor actions to only those available in the given context, making on-demand validation unnecessary.
JustSystems XMAX (XMetaL for ActiveX).
XMAX is the embeddable and web-based version of XMetaL Author. It presents seamless authoring and editing interfaces within common applications such as email, web browsers, and within content management system (CMS) views. It makes XML content authoring easy – no XML knowledge required.
Xopus is a browser based XML editor targeted at people who don't want to have technical knowledge. Xopus hides all actions that would make the XML document invalid. In Xopus someone can edit an XML document in its published format, while Xopus keeps the information separated from the style. Xopus allows you to edit complex XML as if it were a word-processor document.
XML Editors Review by Bob Doyle (including 4 browser-based editors)