Patrick H. Lauke: Evaluating web sites for accessibility with Firefox / Manchester Digital Accessibility Working Group (MDAWG) / 1 March 2006

1. Date or reference
Evaluating web sites for accessibility with Firefox
Patrick H. Lauke
Manchester Digital Accessibility Working Group (MDAWG) - 1/3/2006

2. 1/3/2006 2
Introduction
What we’ll cover:
• no “big secrets revealed”
• short, pragmatic tips on WCAG 1.0 manual checks
• “live” version of short article originally published on Ariadne
• time permitting: short look at TAW3 tool to record check results

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Automated validators
The infamous “Bobby”…(now WebXact)
• Automated accessibility checkers are dumb.
• “Bobby” and co. are just a tool and do not replace human
judgement and checks.
• False positives, false negatives.
All my images have an ALTernate text of “image”…is that
accessible?
Some tools do aknowledge that manual testing is required…

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Firefox + Web Developer Toolbar
Mozilla Firefox combined with Web Developer Toolbar:
cheap (free) and easy way to assist in testing
http://www.mozilla.com/firefox/
http://chrispederick.com/work/webdeveloper/

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• Checkpoint 1.1
Provide a text equivalent for every non-text element
• Outline Images Without Alt Attribute
• Outline Images With Empty Alt Attribute
• Replace Images With Alt Attributes

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Checkpoint 3.2
Create documents that validate to published formal
grammars
• Validate CSS
• Validate HTML
• Validate Local CSS
• Validate Local HTML

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Checkpoint 3.3
Use style sheets to control layout and presentation
• Disable Styles > All Styles

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Checkpoint 3.5
Use header elements to convey document structure and
use them according to specification
Checkpoint 3.6
Mark up lists and list items properly
Checkpoint 3.7
Mark up quotations. Do not use quotation markup for
formatting effects such as indentation
• Options > Show element names when outlining elements
• Outline Block Level Elements

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Checkpoint 4.2
Specify the expansion of each abbreviation or acronym in
a document where it first occurs
• Outline Custom Elements ABBR and ACRONYM

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Checkpoint 5.3
Do not use tables for layout unless the table makes sense
when linearised
• Miscellaneous > Linearise Page

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Checkpoint 6.1
Organise documents so they may be read without style
sheets. For example, when an HTML document is
rendered without associated style sheets, it must still be
possible to read the document
Same as 3.3

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Checkpoint 6.3
Ensure that pages are usable when scripts, applets, or
other programmatic objects are turned off or not
supported
• Disable Java
• Disable Javascript

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Checkpoint 6.4
For scripts and applets, ensure that event handlers are
input device-independent
Checkpoint 9.3
For scripts, specify logical event handlers rather than
device-dependent event handlers
• Just use keyboard

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Checkpoint 9.4
Create a logical tab order through links, form controls,
and objects
• Linearise / disable styles / use keyboard

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Checkpoint 9.5
Provide keyboard shortcuts to important links (including
those in client-side image maps), form controls, and
groups of form controls
• Information > Display Accesskeys

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Checkpoint 11.2
Avoid deprecated features of W3C technologies.
• Outline deprecated elements

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Checkpoint 12.4
Associate labels explicitly with their controls
• Use mouse
• Forms > View Form Information

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Other useful tools
Gez Lemon’s table inspector
http://juicystudio.com/article/firefox-table-inspector.php
Gez’s colour contrast analyser
http://juicystudio.com/article/colour-contrast-analyser-firefox-
extension.php
TAW3 to record manual check findings
http://www.ariadne.ac.uk/issue46/lauke/
http://www.tawdis.net/taw3/cms/en

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