offline.js - Every app goes offline
What is Offline.js?
Offline.js is a library to automatically alert your users when they’ve lost internet connectivity, like Gmail.It captures AJAX requests which were made while the connection was down, and remakes them when it’s back up, so your app reacts perfectly. It has a number of beautiful themes and requires no configuration.
TogetherJS - Free Collaboration features and tools
What is TogetherJS?
TogetherJS is a free, open source JavaScript library by Mozilla that adds collaboration features and tools to your website. By adding TogetherJS to your site, your users can help each other out on a website in real time!