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
