Umbrella JS is described as 'Tiny library for DOM manipulation, events and AJAX' and is an app in the Development category. There are more than 25 alternatives to Umbrella JS for a variety of platforms, including Windows, Linux, Mac, Online / Web-based and Self-Hosted solutions. The best alternative is jQuery, which is both free and Open Source. Other great apps like Umbrella JS are Zepto.js (Free, Open Source), Underscore.js (Free, Open Source), Lodash (Free, Open Source) and DHTMLX (Paid).
Ractive.js is a template-driven UI library that transforms your templates, styles and logic into blueprints for highly interactive apps. Ractive.js works for you, not the other way around. You do not need to learn new terminologies, concepts, and methodologies.