and if i can add there is a w3c editor which I found some time ago but have not have not managed to have a look myself at it yet but being by w3c your coding will be good
Amaya Home Page
Amaya (formerly Amaya World)[4] is a free and open source WYSIWYG web authoring tool[5] with browsing abilities, created by a structured editor project at the INRIA, a French national research institution, and later adopted by the World Wide Web Consortium (W3C). Amaya is used as a testbed for web standards[6] and replaced the Arena web browser.[7][8][9] It is very lightweight, meaning it does not use much computer resources.[10]
W3C's Editor/Browser
Amaya is a Web editor, i.e. a tool used to create and update documents directly on the Web. Browsing features are seamlessly integrated with the editing and remote access features in a uniform environment. This follows the original vision of the Web as a space for collaboration and not just a one-way publishing medium.
Work on Amaya started at W3C in 1996 to showcase Web technologies in a fully-featured Web client. The main motivation for developing Amaya was to provide a framework that can integrate as many W3C technologies as possible. It is used to demonstrate these technologies in action while taking advantage of their combination in a single, consistent environment.
Amaya started as an HTML + CSS style sheets editor. Since that time it was extended to support XML and an increasing number of XML applications such as the XHTML family, MathML, and SVG. It allows all those vocabularies to be edited simultaneously in compound documents.
Amaya includes a collaborative annotation application based on Resource Description Framework (RDF), XLink, and XPointer. Visit the Annotea project home page.