ArtJs is JavaScript framework of general purpose. It allows you to select or manipulate DOM elements, perform AJAX requests, provides load of helper methods for String, Date and other native classes, etc.

Currently it supports FF, Chrome, Safari, Opera, IE8 and IE9.

Zip package contains art.js file that loads appropriate library depending on the browser.
You only need to inlude that file in your head section.
Default load location is set to "javascripts/" but you can change it by setting your own path like this:

Just after library is loaded there are two methods that you may want to use: ArtJs.globalize() and ArtJs.doInjection()

ArtJs.globalize() makes all the classes globally accessible in window object, as well as shorthand utility methods like: $, $$, $P, $B, $D, $DC, $E.

ArtJs.doInjection() makes an extensions on native classes like Object, Array, Date, Element etc. so that you can use:

arr.first();

otherwise you are still able to call the method using:

ArtJs.ArrayUtils.first(arr);