Why are some JavaScript constructors not functions?

Question

Clarification:
\"JavaScript constructor\" should be more properly be written as \"javascript constructor\" to emphasize that the constructors considered are not just the nat

Answer 1

First:

Objects ARE functions

No, the are not:

> a = function() {}
  function () {}
> a instanceof Object
  true
> b = {}
  Object
> b instanceof Function
  false

---

The toString method (which is what gets called when you do string concatenation) is not a reliable way to get information about an object. If I use typeof, I get the following:

using browser environment:  
Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:5.0.1) Gecko/20100101 Firefox/5.0.1

function

function

function

object

function

function

function

So you see, most of them, apart form Storage, are actually functions (why it does not work for Storage, I don't know).

Also keep in mind that the DOM interface can behave differently than native JavaScript objects.

On the other hand, in Chrome the toString method gives this:

[object Function] 

[object Function] 

[object Function] 

function Storage() { [native code] } 

function XMLHttpRequest() { [native code] } 

function Worker() { [native code] } 

function FileReader() { [native code] }