[Accessibility-handlers] updated minutes from 21 april 2008 handlers call

Gregory J. Rosmaita unagi69 at concentric.net
Wed Apr 23 12:36:45 PDT 2008


aloha!

thanks to pete for his additions to the record of the 21 april 2008 handlers
call:

https://www.linux-foundation.org/en/Accessibility/Handlers/Meetings/Minutes20080421.html

i, too, just modified the minutes, adding annotations, links, 
formatting, and (most important/germane), extracts from the Element 
Traversal working draft about which i informed the group (and to which i've 
placed a link as a reference in these and past minutes) during the call...

if anyone else has anything to add, correct or modify, please either do
so yourself (you need to have a linux foundation wiki account to edit 
the minutes) or reply-to this post and i'll effect whatever changes are
necessary...

i'm going to include the important bits about the Element Transversal 
draft after my signature, but if you use the hypertext version of the 
minutes, you will be able to follow the links embedded in the quotes,

gregory.

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Element Traversal Specification:
http://www.w3.org/TR/2008/WD-ElementTraversal-20080303/

    Abstract
        This specification defines the ElementTraversal interface, 
        which allows script navigation of the elements of a DOM tree, 
        excluding all other nodes in the DOM, such as text nodes. It 
        also provides an attribute to expose the number of child 
        elements of an element. It is intended to provide a more 
        convenient alternative to existing DOM navigation interfaces, 
        with a low implementation footprint.

    1. Introduction
        This section is informative.

        The DOM Level 1 Node interface defines 11 node types, but most 
        commonly authors wish to operate solely on nodeType 1, the 
        Element node. Other node types include the Document element and 
        Text nodes, which include whitespace and line breaks. DOM 1 node 
        traversal includes all of these node types, which is often a 
        source of confusion for authors and which requires an extra step 
        for authors to confirm that the expected Element node interfaces 
        are available. This introduces an additional performance 
        constraint.

        ElementTraversal is an interface which allows the author to 
        restrict navigation to Element nodes. It permits navigation from 
        an element to its first element child, its last element child, 
        and to its next or previous element siblings. Because the 
        implementation exposes only the element nodes, the memory and 
        computational footprint of the DOM representation can be 
        optimized for constrained devices.

        The DOM Level 1 Node interface also defines the childNodes 
        attribute, which is a live list of all child nodes of the node; 
        the childNodes list has a length attribute to expose the total 
        number of child nodes of all nodeTypes, useful for preprocessing 
        operations and calculations before, or instead of, looping 
        through the child nodes. The ElementTraversal interface has a 
        similar attribute, childElementCount, that reports only the 
        number of Element nodes, which is often what is desired for such 
        operations.

    2. ElementTraversal interface
        This section is normative.

        The ElementTraversal interface is a set of attributes which allow 
        an author to easily navigate between elements in a document. In 
        conforming implementations of Element Traversal, all objects that 
        implement Element must also implement Element Traversal. Four of 
        the attributes, firstElementChild, lastElementChild, 
        previousElementSibling, and nextElementSibling, each provide a 
        live reference to another element with the defined relationship to 
        the current element, if the related element exists. The fifth 
        attribute, childElementCount, exposes the number of child elements 
        of an element, for preprocessing before navigation. A conforming 
        User Agent must implement all five attributes. A User Agent may 
        implement similar interfaces in other specifications, but such 
        implementation is not required for conformance to this 
        specification, if the User Agent is designed for a minimal code 
        footprint.

        This interface must be implemented on all elements, regardless of 
        their namespace. For the purpose of Element Traversal, an entity 
        reference node which represents an element must be treated as an 
        element node. Navigation must be irrespective of namespace, e.g. 
        if an element in the HTML namespace is followed by element in the 
        SVG namespace, the nextElementSibling attribute on the HTML 
        element will return the SVG element.

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A conclusion is simply the place where someone got tired of thinking.
                                                      -- Arthur Bloc
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   Gregory J. Rosmaita - oedipus at hicom.net AND gregory at ubats.org
        Camera Obscura: http://www.hicom.net/~oedipus/
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