[whatwg] HTML 5 : Misconceptions Documented

Thomas Broyer t.broyer at gmail.com
Wed Aug 6 07:17:33 PDT 2008

On Wed, Aug 6, 2008 at 11:29 AM, Maciej Stachowiak wrote:
> I think Garret has a valid point (despite his needlessly rude tone) that the
> way we describe magical dynamic properties in a way that makes clear they
> are also visible to the "in" operator and to
> Object.prototype.hasOwnProperty. Are there any DOM bindings that have index
> (or named) properties which are *not* visible in such a way?

You mean "ECMAScript binding implementation", right?

Using reflection on a C# class won't give you a property named "0" or
"myform", even though you can get them using myvariable[0] and
If I were to implement a binding in Python, I would do the same
(though « 0 in myvariable » and « "myform" in myvariable » would work
the same as in ECMAScript today; but dir(myvariable) wouldn't show "0"
or "myform")

> If not, then the current [IndexGetter] definition is useless and we need
> a better formalism.

...or rather the ECMAScript binding should define this particularity.

> I think Web IDL should provide a formalism to cater to this, because nearly
> all bindings with special dynamic properties work like this afaik. But I
> think it would have to involve a pseudo-method for the "hasOwnProperty"
> check (which "in" is based on).

hasOwnProperty is ECMAScript-specific.

Thomas Broyer

More information about the whatwg mailing list