Parsley.js : Javascript forms validation.
Powerful, UX aware & Dead simple.
Workbox : JavaScript Libraries for adding offline support to web apps.
Dropzone.js : DropzoneJS is an open source library that provides drag'n'drop file uploads with image previews.
clipboard.js : Copy text to the clipboard shouldn't be hard. It shouldn't require dozens of steps to configure or hundreds of KBs to load. But most of all, it should...
loglevel : Minimal lightweight logging for JavaScript, adding reliable log level methods to wrap any available console.log methods
