“The idea of accessibility of web-based technology is based on far more than the implementation of standards and technological solutions. It embodies the idea that everyone has the right to information and that everyone has the right to be included in society, regardless of disability, geographical location, langauge barriers, or any other factor”. (Introduction)

Chapter 1: Understanding Web Accessibility
“Accessibility is about designing so that more people can use your web site efectively in more situations.” (p. 13)
–Functional limitations pertain to disabilities (visual, auditory, physical, cognitive (including language and learning disabilities)
–Situational limitations relate to the prevailing circumstances (mobile devices, not having a mouse)
Most legal requirements relate to functional limitations.
Between 15 - 30% of the general population of functional limitations that can affect their ability to use technology products. That represents an estimated 50 million people in the US alone, and over 750 million worldwide.

Chapter 2: Overview of Law and Guidelines
WCAG: World Wide Web Consortium Web Content Accessibility Guidelines 1.0 = stable international specification released in May 1999.
Section 508 of the Rehabilitation Act Amendments of 1998, went into effect June 21, 2001.
WAI (Web Accessibility Initiative) launched by W3Cin April 1997 to “promote and achieve Web functionality for people with disabilities”

WCAG Priorities:
Priority 1: a web content developer must satisfy this checkpoint. Otherwise, one or more groups will find it impossible to access information in this document. SAtisfying this checkpoint is a basic requirement for some groups to be able to use web documents.
Priority 2: A web content developer should satisfy this checkpoint. Otherwise, one or more groups will find it difficult to access information in the document. Satisgying this checkpoint will remove significant barriers to accessing web documents.
Priorit 3: A web content developer may address this checkppint. Otherwise, one or more groups will find it somewhat difficult to access information in the document. Satisfying this checkpointwil improve access to web documents.

The majority of Section 508 rules are based on Priority 1, but there additional rules particular to US law.
“Section 508 requires Federal agencies to give disabled employees and members of the public access to information that is comparable to the access available to others.” (p 51)

Chapter 3: Assistive Technology Browsers and Accessibility
Screen readers do not actually read the screen; newer versions use the DOM to determine how to present the information
Common screen readers: JAWS, Window-Eyes
Voice Browser: IBM Home Page Reader
Text Browser: Lynx

Chapter 4: Creating Accessible Content
“The subject of accessibility on the web can be divided into three main categories: accessible web content, accessible navigation, and accessible interaction.”

Text equivalents:
–probably the most important accessibility issue, providing text informationfor web content that is non-textual. Includes images, image maps, image buttons and MM files.

WCAG: 1.1 Provide a text equivalent for every non-text element (for example, via “alt”, “longdesc” or in element content) This includes…
Section 508 1194.22(a) 1.1 Provide a text equivalent for every non-text element (for example, via “alt”, “longdesc” or in element content)

Style of alt text: Book advocates shorter alt text than even the text in an image. A sighted person can edit out “visual noise” but someone listening to the page cannot. e.g. The University of Arizona — alt=”U of A”, Also tends to avoid the words “home page” as that should be evident

Spacer gifs should always have null alt text, that is alt=”"
There is some disagreement on the alt text of stylistic elements, bullets or divider lines. The author advocates (and I agree) using null alt text. These are presentational elements and do not need to be shared with a non-sighted viewer.

There are two mechnisms for providing textual equivalents for non-text content like charts and graphs. The first is the longdesc attibute of an image. The value of the longdesc (long description) attribute is a UI, a reference to another page or a file that contains a detailled description of the content of the image, which ,ust be maintained as data changes. The problem with the longdesc attribute is that it is not widely supported by assistive technology. As a result, an alternative convention is suggestion, using the D-LINK. The D-link is a link to a file o page which is the same as the longdesc value.

<a href=”chart22.gif” width=”455″ height=”325″ alt=”Food sales for 2000″ longdesc=”sales2000.htm”><a href=”sales2000.htm”>D</a>

-Every image, image map area and image button should have a valid alt attribute.
- All images which are not active and do not convey information or are redundant should have alt=”", that is, null alt text.

Transcripts of audio:
If audio is decoration, thee is no need to add text equivalents. When the audio contains spoken words, when it is in fact the message, a textual transcript is required.

Avoiding Use of Color to Convey Information
It is estimated that 1 in 20 visitors to your site will have some for of color visio deficiency. The key is no to use color alone.

Section 508: 1194.22(c) Web pages shall be designed so that all information conveyed with color is also available without color, for example from context or markup.

WCAG: 2.1 Ensure that all information conveyed with colo is also available without color, for example from context or markup.

Creating Accessible Tables
SCreen readers deal with tables differently now than they have in the past. Now, they read the entire contents of a cell when it is encountered, working from top left to top right, then proceeding down to the next row.

WAI 5.3: Do not use tables for layout unless the table makes sense when linearized. Otherwise, if the table does not make sense, provide an alternative equivalent (which may be a linearized version)

Data Tables
Section 508: 194.22(g) Row and column headers shall be identified for data tables.
WCAG 5.1: For data tables, identiy row and column headers.

Using the <th> element and scope attribute
<th> is used to enclose data in a table that is intended to be a heading.
The scope attribute offers an alternative to the th element for specifying header informationin an HTML table.

WCAG: 5.2 For data tables that have two or more logical levels of row or column headers, use markup to associate data cells and header cells (Priority 1)

Section 508: 1194.22(g) Markup shall be used to associate data cells and header cells for data labels that have two or more logical levels of row or column headers.

Avoiding flicker
7.2 Until user agents allow users to control flickering, avoid causing the screen to flicker.

Summary:
–Avoid duplicate adjacent links. if both an image and text are links on the same href, enclose them both in the same anchor tag, and then place alt=”" on the image. Unside a BUTTON element put non-null alt text on any image to the extent that the information conveyed by the image is not redundant.

Chapter 5: Accessible Navigation
Major topics:
1. skip links
2. accessible frames
3. accessible image maps
4. how layout can affect navigation
5. accessible links

Guidelines for Skipping Navigation
Section 508: 1194.22(o) A method shall be provided that permits users to skip repetitive navigation.

Three methods to provide skip navigation include:
- placing the link in normal text
- creating a link as alt text on an image that doesn’t carry information
- using a text link with the same foreground and background colors
(one example of skip nav is taken from LDC!)