Cameron McCormack wrote:
This is probably not what browsers do in practice, though. For example,
Opera 9 has an addEventListener method directly on the Node interface
prototype object
What Gecko does is to put all properties for all the interfaces an object
implements onto the "closest" prototype object. So if you have a <div>,
HTMLDivElement.prototype will have all the properties the <div> is supposed to
have defined directly on it.
The prototype chain in Gecko basically follows the inheritance model in the DOM
spec: HTMLDivElement.prototype.[[Prototype]] === HTMLElement.prototype, etc.
Things like EventTarget are off to the side somewhere as in your imagined way to
handle it.
As a result, given a <div> object (call it "div"),
div.[[Prototype]] === HTMLDivElement.prototype
HTMLDivElement.prototype.[[Prototype]] === HTMLElement.prototype
div.appendChild === HTMLDivElement.prototype.appendChild
are all true, while
div.appendChild === HTMLElement.prototype.appendChild
is false. As a result, to change what the appendChild of a <div> is you have to
change it on HTMLDivElement.prototype.
Of course all of this is subject to change, and in fact is likely to change some
time in the not too distant future.
To be honest, do we really think that specifying the exact prototype chain is
desirable? How likely are UAs to rework the mappings between their native code
and ECMAScript to follow said spec?
-Boris
