javascript - How does jQuery makes the jQuery object both a function and an object property? -

i've been wondering long time how jquery can both function , object property.

you can use function, jquery(...) , can use property jquery.ajax(...)

how can achieve such thing in javascript?

functions objects in javascript. can have main function

var $ = function() {  alert('wat'); } 

and extend it

$.fadeto = function() { alert('fadeto'); }