On Wed, 25 Nov 2009 21:46:59 +0100, Klotz, Leigh <leigh.kl...@xerox.com>
wrote:
This comment on XMLHttpRequest [1] is from the Forms WG.
A standalone W3C Recommendation-track document is welcome, particularly
because of the statement in [2] "The goal of this specification is to
document a minimum set of interoperable features based on existing
implementations, allowing Web developers to use these features without
platform-specific code." This goal was widely quoted in web discussion
on the working drafts, and is no doubt an attractive feature of a
standalone specification document.
Note that we changed this goal slightly because documenting the mimimum
set of interoperable features did not work very well once you went beyond
a certain level of detail.
The XMLHttpRequest functionality described in this document has
previously been well isolated, and in fact XHR itself has beeen
implemented by a number of different desktop browser vendors by copying
the original implementations.
It appears that the current draft, howevever, has a wide dependence on
HTML5: [3] "This specification already depends on HTML 5 for other
reasons so there is not much additional overhead because of this."
This is not new, actually, but alas.
That dependence runs counter to the goals of allowing Web developers to
use the features without platform-specific code.
Why would that be? HTML5 is not platform-specific.
While it may be useful for the HTML5 specifications to include
XMLHTTPRequest and make enhancements to it, the dependency should be
from HTML5 on XMLHttpRequest, and not vice versa. Making XMLHttpRequest
depend on HTML5 causes problems with non-HTML5 implementations of the
feature.
HTML5 is the only specification that defines several core concepts of the
Web platform architecture, such as event loops, event handler attributes,
etc.
In summary, we feel that the dependencies between HTML5 and
XMLHttpRequest are in the wrong direction. We ask that the dependency
on HTML5 be eliminated, and that the XMLHttpRequest Working Draft be
changed to specify minimum requirements for integration in the areas for
which it depends on HTML5. The HTML5 document itself can surely satisfy
these requirements.
I do not think it makes sense that a user agent that implements e.g. HTML5
and SVG would have two implementations of XMLHttpRequest. HTML5 simply
defines some core underlying concepts and these will be the same
everywhere. There are indeed things that can differ depending on the
context and those have been abstracted out, as you found. Mostly to
facilitate Web Workers, but I can imagine these hooks might be used
elsewhere too.
[1] http://www.w3.org/TR/2009/WD-XMLHttpRequest-20091119
[2] http://www.w3.org/TR/2006/WD-XMLHttpRequest-20060405/
[3] http://www.w3.org/TR/2009/WD-XMLHttpRequest-20091119/#dependencies
(I corrected the numbering here.)
--
Anne van Kesteren
http://annevankesteren.nl/
