wysihtml is an extended and less strict approach on xing/wysihtml5 open source rich text editor based on HTML5 technology. The code is completely library agnostic: No jQuery, Prototype or similar is required.
Auto linking of urls as-you-type
Generates valid and semantic HTML5 markup
Can use class-names instead of inline styles
Unifies line-break handling across browsers
Auto-parses content inserted via copy & paste (from Word, Powerpoint, PDF, other web pages, etc.)
Converts invalid or unknown html tags into valid/similar tags
Source code view for users with HTML skills
Uses sandboxed iframes in order to prevent identity theft through XSS.
Editor inherits styles and attributes (placeholder, autofocus, etc.) from original textarea (you only have to style one element).
Speech-input for Chrome