Prototype : Easy Ajax and DOM manipulation for dynamic web applications
Push by Nickersoft : A compact, cross-browser solution for using the JavaScript Notifications API
Closure Tools : The Closure Compiler, Library, Templates, and Stylesheets help developers create powerful and efficient JavaScript.
Passport : Passport is authentication middleware for Node.js. Extremely flexible and modular, Passport can be unobtrusively dropped in to any Express-based web a...
Dropzone.js : DropzoneJS is an open source library that provides drag'n'drop file uploads with image previews.
nlp_compromise does NLP in the browser. It's a handy, and not overly-fancy tool for understanding, changing, and playing with english. We've also got a modest, though ambitious plugin ecosystem.