ProseMirror : In-browser structured text editing component. A toolkit for building rich-text editors on the web.
impress.js : It's a presentation framework based on the power of CSS3 transforms and transitions in modern browsers and inspired by the idea behind prezi.com
howler.js : howler.js is an audio library for the modern web. It defaults to Web Audio API and falls back to HTML5 Audio.
Logerr : Experimenting with window.onerror, trying to make JavaScript debugging easy.
What does it do?
Provides JavaScript error details in a readable format. ...
enquire.js : A lightweight, pure JavaScript library for responding to CSS media queries.
JavaScript Libraries for adding offline support to web apps.