[TECHS] draft introduction to client side scripting techniques

I recently posted a proposal for three categories of client side scripting 
techniques along with a set of possible technique ideas for each category 
[1].  Below is a rough draft of the introduction to the client side 
techniques document explaining the categories and how an author can 
determine what set of techniques to use.   The goal is to provide guidance 
on making baseline issues by grouping the techniques by functionality. 
Please review this introduction and the list of techniques to determine:
1) do these categories makes sense and are they adequately described? 
2) are the techniques listed for each category appropriate?
3) are they listed in the correct category?

Currently the proposed techniques are not mapped back to a specific 
guideline. That mapping will need to occur before they can be considered 
for inclusion in the scripting techniques document.

The introduction has also been attached as a Word document.

Introduction
This is the Client-side Scripting Techniques for Web Content Accessibility 
Guidelines 2.0 [WCAG20] This document describes techniques for authoring 
accessible ECMAScript-based scripts. ECMAScript is defined by the ECMA-262 
specification [ECMA262].
This document is intended to help authors of Web content who wish to claim 
conformance to WCAG 2.0. While the techniques in this document should 
increase overall accessibility of Web resources, they are not a 
comprehensive resource for script accessibility. 
WCAG 2.0 does not provide an explicit baseline of technologies that must 
be adhered to when authoring web content.   This is a different approach 
from WCAG 1.0 [WCAG10] Checkpoint 6.3 "Ensure that pages are usable when 
scripts, applets, or other programmatic objects are turned off or not 
supported. If this is not possible, provide equivalent information on an 
alternative accessible page."  Thus, equivalents for scripted content are 
no longer required by WCAG 2.0, but the author must consider the web site 
audience, user agents, and assistive technologies when developing for the 
web.   In addition, all authors must assume that persons with disabilities 
will access the site. Thus, any scripting used must be accessible.  
While web content authored to run without scripting enabled will be the 
most universally accessible, it is not always possible to build more 
complicated web sites or web applications without the use of client side 
scripting.  The UAAG 1.0 provides guidance on browser integration of 
scripting languages in Guideline 6. Implement interoperable application 
programming interfaces .  Authors using scripts must do so in a manner 
such that the scripts can be run in user agents conforming to UAAG 1.0 
Guideline 6.  In addition, the result of the script execution must be 
accessible with the user agents and assistive technologies used by the 
site?s target audience.  
To assist the web author in developing content using client side 
scripting, the techniques in this document are divided into three 
categories:
1.      No Script - Best practices for authoring content that will work 
properly with or without support for client side scripting.
2.      Scripting Enhancements - Client side scripting techniques that 
enhance the accessibility or usability of a site for persons with 
disabilities. These techniques assume that scripting is supported and 
turned on in the user agents and assistive technologies used by the target 
audience. 
3.      Accessible Scripting - Best practices for writing scripts that are 
accessible to user agents which conform to Guideline 6 of UAAG.  These 
techniques do not necessarily improve the accessibility of the web 
content, but they may increase the usability or performance without 
harming access by persons with disabilities.  
An author using techniques from the Scripting Enhancement and Accessible 
Scripting categories must be certain that the expected audience has access 
to user agents and assistive technologies that support scripting.  When 
possible, user agent and assistive technology support for each technique 
is noted. 
At the time of publication, it is assumed that user agents and assistive 
technologies that support the techniques in the Scripting Enhancements 
category are generally available in most common languages found on the 
Web.  However, the category of techniques used must be based on the 
expected audience of the web content.  The audience assumptions may be 
dictated by policy in a given country, organization or governing body.  
The web author is responsible for understanding the policies in affect for 
the content when it is published and writing to that level of support. 

 
[1] http://lists.w3.org/Archives/Public/w3c-wai-gl/2005AprJun/0153.html

Becky Gibson
Web Accessibility Architect
                                                       
IBM Emerging Internet Technologies
5 Technology Park Drive
Westford, MA 01886
Voice: 978 399-6101; t/l 333-6101

Email: gibsonb@us.ibm.com