.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.

jQuery.cssHooks

Hook directly into jQuery to override how particular CSS properties are retrieved or set, normalize CSS property naming, or create custom properties.

jQuery.each()

A generic iterator function, which can be used to seamlessly iterate over both objects and arrays. Arrays and array-like objects with a length property (such as a function’s arguments object) are iterated by numeric index, from 0 to length-1. Other objects are iterated via their named properties.