> hash = {a:1}
Object { a: 1 }

> typeof hash
"object"

> array = [0,1,2]
Array(3) [ 0, 1, 2 ]

> typeof array
"object"

> array.__proto__
Array []

> array.__proto__.__proto__
Object { … }

##</code><code>##

> h={}                         // empty hash?
Object {  }

> h["constructor"]             // well, beware of inherited attributes
function Object()

##</code><code>##

> h = Object.create(null)
Object {  }

> h["constructor"]
undefined