This document compares several major JavaScript libraries, frameworks, and toolkits to help determine which is best for a given project. It defines the differences between libraries, frameworks, and toolkits. Features like modularity, code structure, utilities, and user interface capabilities are compared for libraries like jQuery, MooTools, AngularJS, BackboneJS, Dojo and YUI. Considerations around when to use MV* patterns and support, community, and usage statistics are also discussed.