This page contains material related to a presentation at the Web Accessibility Best Practices Evaluation Training in Sankt Augustin, Germany on 25 October, 2005, as part of the WAI-TIES Project (WAI - Training, Implementation, Education, Support). It is not intended to stand-alone; rather, it is primarily provided as reference material for participants in the training.
Scope of Training and Materials: This one-day training focused on select topics that were particularly suited to the circumstances of this specific training session. It did not to cover all aspects of evaluating Web accessibility, and did not cover all Web Content Accessibility Guidelines (WCAG) 1.0 checkpoints.
No Endorsement or Recommendation of Evaluation Tools: W3C/WAI does not endorse Web accessibility evaluation tools and does not recommend one tool over another. Some tools were listed, demonstrated, and used in activities in this training. Mention of a specific tool does not imply endorsement nor recommendation. WAI does provide a comprehensive list of Evaluation, Repair, and Transformation Tools for Web Content Accessibility.
Evaluating Navigation
Andrew Arch, Vision Australia - Accessibility Information Solutions
Last updated: 1 November 2005
Purpose of Navigation
- Navigation is the essence of the web experience
- Menus and in-page links are the means of navigation ...
- To go to a new page
- To move to another position on the current page
- Opera, JAWS, HPR and others also allow navigation by Headings and other structure
Accessibility is experiential
- Assume your uers have been to all other websites before they come to yours
- A person with a disability/impairment should be able to use data, information and services as effectively as someone without a disability
- Compliance with technical rules is necessary, but not sufficient
Issues for People With Disabilities #1
- Not necessarily using a mouse:
- Might be able to see the screen well, but may be using the keyboard or a switch device to navigate
- Expecting to navigate by keyboard in the visual display order
- Tabbing between links and form controls
- Using other keys to move between (and around) headings, tables, lists, etc
- Skipping over common navigation is useful
- Accesskeys can be useful (but beware of conflicts)
Issues for People With Disabilities #2
- May be slow readers
- Suffering from reading disability such as dyslexia
- Other cognitive issues such as Attention Deficit Disorder
Issues for People With Disabilities #3
- May have poor eyesight and low contrast acuity
- Fact of aging as well as result of some vision impairments
- Can the user determine which text is actually the link?
Issues for People With Disabilities #4
- Not necessarily viewing the whole screen
- May be using a screen magnifier
- Positioning becomes important
- Self-referential link become confusing
- Front-loaded links become important
Issues for People With Disabilities #5
- Not necessarily even viewing the screen at all
- So, links may be out of context from their surrounding text
- "More" or "Click Here" not useful
- Self-referential links (that reload the current page) create confusion
- "bad" links (404 errors; wrong page) not expected
- Files downloads not expected
- Screen reader users also get semantic information such as headings and lists
WCAG 1.0 Checkpoints - Navigation
- 6.4 For scripts and applets, ensure that event handlers are input device-independent
- 9.4 Create a logical tab order through links, form controls, and objects
- 13.1 Clearly identify the target of each link
- 13.6 Group related links [...] provide a way to bypass the group
WCAG 1.0 Checkpoints - Structure
- 3.5 Use header elements to convey document structure and use them according to specification
- 3.6 Mark up lists and list items properly
- 13.8 Place distinguishing information at the beginning of headings, paragraphs, lists, etc
Testing Navigation order
- Tabbing order should approximate visual display order
- Tab through a page in IE
- Navigate by headings in Opera
- Check for "tabindex"
- Use the AIS Web Accessibility Toolbar in IE
- Check for access keys
- Use the Developers Toolbar in Firefox
- Check for "skip to content"
- Is it visible?
- Does it work with the keyboard? (Beware of the IE bug.)
Testing navigation for device independence
- Menus
- Can you tab to all the top menu items?
- Is there an intermediate page with the "fly-out" / "drop-down" options?
- What happens to the menu if JavaScript is disabled (do this and test)
- Links
- Can you access the list in the "quicklinks"?
- Can you tab to all the apparent links?
- Be aware that links created purely with JavaScript cannot receive keyboard focus
Testing link clarity
- Are the links clear if considered out of context?
- Bring up a list of links (Opera: Ctrl-Alt-l)
- Do they all make sense?
- Are they "scan-able"?
- Are any document downloads clearly identified?
- Could you clearly see all the links identified?
- Were there any hidden links?
Testing Reading order
- Reading order should approximate visual display order
- Use Aprompt to show table cell reading order
- Use the WAVE to show reading order
- Use IE or Firefox toolbars to disable CSS
- Discuss the page with a screen-reader user (or use HPR/JAWS yourself)
Testing structure & semantics
- Headings and lists
- Are they in the content layer or just the presentation layer?
- Use the WAVE to reveal structural markup
- Use AIS Toolbar in IE to reveal heading structure