Is anyone aware of any HTML5 based language editor with content assist?

Question

Does anyone know of a project that will allow the editing of a language (any language) within a web-page itself (via HTML-5) with content assist (ctrl+space)?

CLARIFICATION

I'm not looking for a HTML5 editor (I'm aware of many), I'm looking for a language editor written in HTML5/Javascript that runs within a browser.

Answer 1

Bespin is an experimental web-based IDE written by the Mozilla team which can be used to edit HTML and JS (and presumably any other kind of) files.

Answer 2

You can get HTML5 Intellisense for Visual Studio here.

Answer 3

Adobe DreamWeaver CS5 has the content assist (in Javascript and HTML) for HTML5 Canvas and probably other elements in HTML5 specification