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Re: Fallout of non-encapsulated shadow trees

From: Boris Zbarsky <bzbarsky@MIT.EDU>
Date: Wed, 02 Jul 2014 11:13:49 -0400
Message-ID: <53B421AD.3060506@mit.edu>
To: Adam Barth <w3c@adambarth.com>
CC: WebApps WG <public-webapps@w3.org>, Maciej Stachowiak <mjs@apple.com>
On 7/2/14, 11:07 AM, Adam Barth wrote:
> I've studied the XBL implementation of <marquee> in Gecko, and it does
> leak some implementation details.

Absolutely.  The point of the XBL implementation was to provide the 
functionality (back before there was a spec for it, note) at minimal 
cost and core complexity.  It's not even close to what hixie has specced 
for marquee right now.

> As a simple example,
> alert(document.createElement('marquee')) in Firefox says "[object
> HTMLDivElement]" because the XBL implementation uses a div.

It's because XBL doesn't have a way to affect the sort of JS object 
that's created for the element and we explicitly map the "marquee" tag 
name to creating an HTMLDivElement C++ object because we didn't really 
have any better sort of C++ object for it to create.

Web components can help solve parts of this "what sort of JS object to 
create?", I agree.

-Boris
Received on Wednesday, 2 July 2014 15:14:19 UTC

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