Mercury Editor is a fully featured editor much like TinyMCE or CKEditor, but with a different usage paradigm. It expects that an entire page is something that can be editable, and allows different types of editable regions to be specified.

It displays a single toolbar for every region on the page, and uses the HTML5 contentEditable features on block elements, instead of iframes, which allows for CSS to be applied in ways that most other editors can’t handle. Mercury has been written using CoffeeScript and jQuery for the Javascript portions, and is written on top of Rails 3.1.

Requirements: Chrome 10+, Safari 5+, Firefox 4+
Demo: http://jejacks0n.github.com/mercury/
License: MIT License