TraceKit : Not all browsers support stack traces on error objects, but TraceKit squeezes out as much useful information as possible and normalizes it.
Firebug Lite : A JavaScript file you can insert into your pages to simulate the Firebug console in browsers that are not named Firefox.
Babel : Babel will turn your ES6+ code into ES5 friendly code, so you can start using it right now without waiting for browser support.
DOM Monster Bookmarklet : DOM Monster is a cross-platform, cross-browser bookmarklet that will analyze the DOM & other features of the page you're on, and give you its bill of ...
PouchDB : PouchDB is a JavaScript library that allows you to store and query data for web applications that need to work offline, and sync with an online databa...