Why does jQuery.fn display [] in the console?

jQuery.fnjust matches the array requirements for developer consoles . This is not an actual instance Array*, but it has an interface that allows you to process an array.

_{* If it jQuery.fnwas actually an array, jQuery.fn instanceof Arraywould appreciate true; this is not true. However, it copies some of the methods Array.prototype.}

, Array, , - obj instanceof Array, , Array. , , , Array, :

function isArray(arg) {
    return Object.prototype.toString.call(arg) === '[object Array]';
}

:

var a, b;
function Foo() {}
Foo.prototype = [];
a = new Foo();
b = [];
a instanceof Array; //true
b instanceof Array; //true
isArray(a);         //false
isArray(b);         //true