vue.js : Vue.js is a library for building interactive web interfaces. It provides data-reactive components with a simple and flexible API. Core features includ...
Headroom.js : Headroom.js is a lightweight, high-performance JS widget (with no dependencies!) that allows you to react to the user's scroll.
Leaflet : A Modern, Lightweight Open-Source JavaScript Library for Interactive Maps
rsvp.js : A lightweight library that provides tools for organizing asynchronous code
script.aculo.us : script.aculo.us provides you with
easy-to-use, cross-browser user
interface JavaScript libraries to make
your web sites and web applications fly.
For web application developers, the '''JavaScript Templates''' engine from TrimPath is a lightweight APL / GPL open-source component that lets you have template-based programming (like PHP/ASP/JSP) while running in a web browser