wysihtml5 is an open source rich text editor based on HTML5 technology and the progressive-enhancement approach. It uses a sophisticated security concept and aims to generate fully valid HTML5 markup by preventing unmaintainable tag soups and inline styles.

It’s fast and lightweight. It generates valid and semantic HTML5 markup. It uses class names instead of inline styles. It supports speech-input for Chrome as well. It is released under MIT License.

Requirements: JavaScript Framework
Demo: http://xing.github.com/wysihtml5/
License: MIT License