HTML 5 WYSIWYG Editor

Open source rich text editor based on HTML5 and the progressive-enhancement approach. Uses a sophisticated security concept and aims to generate fully valid HTML5 markup by preventing unmaintainable tag soups and inline styles. http://jhollingworth.github.io/bootstrap-wysihtml5/

CKEditor

CKEditor is a ready-for-use HTML text editor designed to simplify web content creation. It's a WYSIWYG editor that brings common word processor features directly to your web pages. http://ckeditor.com/