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.

.promise()

Return a Promise object to observe when all actions of a certain type bound to the collection, queued or not, have finished.

.has()

Reduce the set of matched elements to those that have a descendant that matches the selector or DOM element.