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.

.is()

Check the current matched set of elements against a selector, element, or jQuery object and return true if at least one of these elements matches the given arguments.