.css()

Get the value of a computed style property for the first element in the set of matched elements or set one or more CSS properties for every matched element.

jQuery.Deferred()

A factory function that returns a chainable utility object with methods to register multiple callbacks into callback queues, invoke callback queues, and relay the success or failure state of any synchronous or asynchronous function.

.closest()

For each element in the set, get the first element that matches the selector by testing the element itself and traversing up through its ancestors in the DOM tree.