Up until this point, all jQuery methods that we've used have been attached to a jQuery object that we've built with the $() function. The selectors have allowed us to specify a set of DOM nodes to work with, and the methods have operated on them in some way. This $.getJSON() function, however, is different. There is no logical DOM element to which it could apply; the resulting object has to be provided to the script, not injected into the page. For this reason, getJSON() is defined as a method of the global jQuery object (a single object called jQuery or $ defined once by the jQuery library), rather than of an individual jQuery object instance (the object returned by the $() function).
If $ were a class $.getJSON() ...
