YUI is described as 'Free, open source JavaScript and CSS library for building richly interactive web applications' and is a javascript framework in the development category. There are seven alternatives to YUI for Web-based, Self-Hosted, JavaScript and jQuery. The best YUI alternative is jQuery, which is both free and Open Source. Other great apps like YUI are Dojo Toolkit, Umbrella JS, smaloa and Prototype JS.
jQuery is a fast, small, and feature-rich JavaScript library. It makes things like HTML document traversal and manipulation, event handling, animation, and Ajax much simpler with an easy-to-use API that works across a multitude of browsers.
jQuery is the most popular Self-Hosted alternative to YUI.
jQuery is the most popular Open Source & free alternative to YUI.
Dojo Toolkit is an open source modular JavaScript library (or more specifically JavaScript toolkit) designed to ease the rapid development of cross-platform, JavaScript/Ajax-based applications and web sites.
Dojo Toolkit is the most popular Web-based alternative to YUI.
smaloa is an easy yet powerful javascript library mainly used for DOM processing, visual effects and project structuring. Easy to learn and hard to master.
Prototype is a JavaScript Framework that aims to ease development of dynamic web applications. Prototype provides various functions for developing JavaScript applications. The features range from programming shortcuts to major functions for dealing with XMLHttpRequest.
Want to use Vanilla JS but find native APIs a bit unwieldy? Bliss is for you.
PKIjs is a pure JavaScript library implementing the formats that are used in PKI applications (signing, encryption, certificate requests, OCSP and TSP requests/responses). It is built on WebCrypto (Web Cryptography API) and requires no plug-ins.
United States
Spain
EU
Greece
YUI is much more than a DOM manipulation tool, it features complex widgets and tools for dialog panels, data tables, drag and drop elements, etc.
Even the prolific jQuery library is a poor comparison without jQueryUI and a host of other plugins.