- From: Boris Zbarsky <bzbarsky@MIT.EDU>
- Date: Wed, 06 Jun 2007 00:15:33 -0500
- To: public-webapi@w3.org
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
Received on Wednesday, 6 June 2007 05:15:46 UTC