WYSIWYG editors

Lightweight versions

• PunyMCE, from the authors of TinyMCE
• NiceEdit
• WysiHat (Prototype)
• widgEditor
• WYMeditor (jQuery)
• jWYSIWYG (jQuery) GitHub
• ggEdit (MooTools)
• YUI Rich Text Editor - SimpleEditor (YUI)
• uEditor (jQuery)
• Loki
• MooRTE (MooTools)
• WMD - Markdown Editor
• goog.editor (Closure Library) Demo
• lwrte (jQuery)
• wkrte (jQuery)
• jHtmlArea (jQuery)
• TinyEditor (jQuery)
• Aloha Editor
• dijit.Editor (Dojo)
• CLEditor (jQuery)
• wysihtml5
• mfpEditor
• Create
• Hallo
• WYSIWYG (jQuery)
• Redactor (jQuery)
• WysiBB - BBcode editor (jQuery)
• ContentTools - A beautiful & small content editor

Heavyweights

• TinyMCE
• FCKeditor
• CKEditor (next generation of FCKeditor)
• YUI Rich Text Editor - Editor (YUI)
• elRTE (jQuery UI)
• Mercury Editor (jQuery, CoffeeScript, Rails)

References

• cheeaun's "Alternative Javascript WYSIWYG editors"