Summernote!

TinyMCE is a platform independent web based Javascript HTML WYSIWYG editor control released as Open Source under LGPL by Moxiecode Systems AB. It has the ability to convert HTML TEXTAREA fields or other HTML elements to editor instances. TinyMCE is very easy to integrate into other CMS systems.

CKEditor is an open source WYSIWYG rich text editor and collaboration solution designed to bring common word processor features directly to web pages, simplifying their content creation.

Trumbowyg is a very small jQuery plugin (16 kB minified) for creating a powerful WYSIWYG editor. Features:

Alloy Editor is a modern WYSIWYG editor built on top of CKEditor, designed to create modern and gorgeous web content.

A lightweight WYSIWYG BBCode & HTML editor

CLEditor is an open source jQuery plugin which provides a lightweight, full featured, cross browser, extensible, WYSIWYG HTML editor that can be easily added into any web site.

Aloha Editor is an HTML5 WYSIWYG Editor that gives you a total new experience when editing. It's faster than existing WYSIWYG technologies and offers unprecedented WYSIWYG functionalities.

Redactor Text Editor is a WYSIWYG html editor.Redactor provides smooth and clean design, limitless flexibility and extensibility, simple and super-efficient API and amazing user experience.

MediumEditor is a Medium.com WYSIWYG editor clone, a dead simple inline editor toolbar. Uses contenteditable API to implement a rich text solution.

Modern WYSIWYG HTML5 editor

ORY Editor is a React based editor for the web built that follows some important principles in modern web development.

React Rich Text Editor is a UI component built completely in React that is meant to be a full-featured textarea replacement. It's based on the excellent, open source Draft.js from Facebook which is performant and production-tested.