Ext JS
23,669 websites

Ext JS offers both free and paid options

https://www.sencha.com/products/extjs/#overview

Ext JS is a cross-browser JavaScript library for building rich internet applications.

VS

MooTools
192,033 websites

MooTools is free to use

http://mootools.net/

MooTools is a collection of JavaScript utilities designed for the intermediate to advanced JavaScript developer. It allows you to write powerful and flexible code with its elegant, well documented, and coherent APIs.

Market Share by Top Websites

1 MooTools is leading in Top 100K Sites, Top 1M Sites and The Entire Web.

2 Ext JS is leading in Top 10K Sites.

Websites Categories

1 MooTools has better usage coverage in more websites categories. Including Science & Education, Computers Electronics & Technology, Law & Government, Health and 20 other categories.

2 Ext JS hasn't got a lead over MooTools in any websites category.

Geography

1 MooTools is leading in most countries, including Russia, United States, Germany, Italy and 156 other countries.

2 Ext JS is leading in China, South Korea, Virgin Islands and U.S..