This jQuery XHR object, or "jqXHR," returned by $.get() implements the Promise interface, giving it all the properties, methods, and behavior of a Promise (see Deferred object for more information). The jqXHR.done() (for success), jqXHR.fail() (for error), and jqXHR.always() (for completion, whether success or error; added in jQuery 1.6) methods take a function argument that is called when the request terminates.
get definition: 1. to obtain, buy, or earn something: 2. to receive or be given something: 3. to go somewhere and…. Learn more.
index. Type: Integer. A zero-based integer indicating which element to retrieve. The .get () method grants access to the DOM nodes underlying each jQuery object. If the value of index is out of bounds — less than the negative number of elements or equal to or greater than the number of elements — it returns undefined.