How is jQuery's $ a function and an object?

Question

I mean object as in {} [object Object]. How does it do $(selector) and $.fn.init at the same time?

Can you give me a simple ex

Answer 1

var q=function(){};

var s = function(){
    alert("base");
    window.s = s;
    return new q()};

q.fn = q.prototype = {};

q.fn.x = s.x = function(){alert("x");return this;};
q.fn.y = s.y = function(){alert("y");return this;};
q.fn.z = s.z = function(){alert("z");return this;};

s().y().z().x();
s.z().x().y();