.data()

Store arbitrary data associated with the matched elements or return the value at the named data store for the first element in the set of matched elements.

jQuery.support

A collection of properties that represent the presence of different browser features or bugs. Intended for jQuery’s internal use; specific properties may be removed when they are no longer needed internally to improve page startup performance. For your own project’s feature-detection needs, we strongly recommend the use of an external library such as Modernizr instead of dependency on properties in jQuery.support.