Isjs
Check your data against regular expressions or known keywords.
Social Count
Simple barebones project to show share counts from various social networks.
Serenade.js
Client side MVC framework
Covervid
Make your HTML5 video behave like a background cover image with this lightweight Javascript plugin / jQuery extension
Multi Select
A user-friendlier drop-in replacement for the standard select with multiple attribute activated.
Convnetjs
Deep Learning in Javascript. Train Convolutional Neural Networks (or ordinary ones) in your browser.
Timezone Js
Timezone-enabled JavaScript Date object. Uses Olson zoneinfo files for timezone data.
Mithril.js
A Javascript Framework for Building Brilliant Applications
Tabslet
Yet another jQuery plugin for tabs, lightweight, easy to use, mobile-friendly and with some extra features.
jScrollPane
Pretty, customisable, cross browser replacement scrollbars
Webfontloader
WebFont Loader gives you added control when using linked fonts via @font-face.
Vorlonjs
A new, open source, extensible, platform-agnostic tool for remotely debugging and testing your JavaScript. Powered by node.js and socket.io
Vegas
Vegas is a jQuery plugin to add beautiful fullscreen backgrounds to your webpages. It even allows Slideshows.
Trace Kit
Attempts to create stack traces for unhandled JavaScript exceptions in all major browsers.
JS Plumb
jQuery/MooTools/YUI3 Javascript library that lets you connect parts of your UI together.
G2 Plot
:dango: An interactive and responsive charting library
Editor
Next-gen, highly customizable content editor for the browser - based on React and Redux. WYSIWYG on steroids.