Function: addClass(domElementOrNodeArrayOrCSSSelector, stringClassName)

Description: Adds one or more space delimited class names to the specified element or set of matching elements.

Returns: domElement or matching node array, or $A object if chained.

Note: Automatically recognizes when previous class names have been set on the same element and appends them accordingly, or ignores them if the same class names have already been set. 

Example:

// Using a DOM node as reference
var myElement = $A.addClass(domElement, "clearfix help-popup");

// Using a DOM node array as reference
var myElementsArray = $A.addClass([domElement1, domElement2], "highlight bold");

// Using a CSS selector as reference
var myElementsArray = $A.addClass("div.error", "bold");

// Or the same using chaining

// Using a DOM node as reference
var myChain = $A(domElement).addClass("clearfix help-popup");

// Using a DOM node array as reference
var myChain = $A([domElement1, domElement2]).addClass("highlight bold");

// Using a CSS selector as reference
var myChain = $A("div.error").addClass("bold");

// To return the modified element within a chain, use the "return()" method.

var myElement = myChain.return();