Markup jQuery Editor: markItUp
Released under both the MIT and GPL Open Source licenses, markItUp is a free and open source JavaScript plugin built on the jQuery library. It allows you to turn any textarea into a markup editor. Html, Textile, Wiki Syntax, Markdown, BBcode or even your own Markup system can be easily implemented.
markItUp is not meant to be a “Full-Features-Out-of-the-Box”-editor. Instead it is a very lightweight, customizable and flexible engine made to meet the developer’s needs in their CMSes, blogs, forums or websites. markItUp is not a WYSIWYG editor, and it never will be.