DOM Traversal Methods

DOM Traversal Methods
Cause there's a train coming into the station
But it's heading for a new destination
—Devo,
"It Doesn't Matter to Me"
In addition to the selector expressions described in Chapter 2, jQuery has a variety
of DOM traversal methods to help us select elements in a document. These methods
offer a great deal of flexibility, even allowing us to act upon multiple sets of elements
in a single chain, like so:
$('div.section > p').addClass('lit').lt(1).addClass('profound');
At times the choice between a selector expression and a corresponding DOM
traversal method is simply a matter of taste, but there is no doubt that the combined
set of expressions and methods makes for an extremely powerful toolset for getting
anything we want.
As of jQuery 1.1, DOM traversal methods do not modify the jQuery object they are
sent to. Instead, a new jQuery object is constructed, which contains a reference to the
original object. The original objec t can be retrieved with the .end method.
The jQuery Factory Function
The following function underpins the entire jQuery library as it allows us to create
the jQuery objects that all of the other methods are attached to.