Bottery : Bottery is a syntax, editor, and simulator for prototyping generative contextual conversations modeled as finite state machines.
Slate : Slate is a completely customizable framework for building rich text editors.
Slate lets you build rich, intuitive editors like those in Medium, Dropbo...
EtherPad : Etherpad is an Open Source online editor providing collaborative editing in really real-time powered by Node.js
NicEdit : WYSIWYG Content Editor, Inline Rich Text Application
Closure Tools : The Closure Compiler, Library, Templates, and Stylesheets help developers create powerful and efficient JavaScript.
MobWrite converts forms and web applications into collaborative environments. Create a simple single-user system, add one line of JavaScript, and instantly get a collaborative system.