Accessibility Assessment
Introduction
There are numerous tools on the internet which can help a developer meet different levels of web accessibility. However, these tools only provide a basic, automatic check of a site and should not be relied upon completely. This article will discuss different automated tests available to developers and address the draw backs they provide.
Accessibility Checkers
There are two main standards of accessibility on the web, Section 508 and the W3C's Web Content Accessibility Guidelines (WCAG). There are numerous tools which allow web developers to check their pages against these varying levels of accessibility.
There are two main, general accessibility checkers, these are Bobby and Cynthia Says.
Bobby
This free service will allow you to test web pages and help expose and repair barriers to accessibility and encourage compliance with existing accessibility guidelines, such as Section 508 and the W3C's WCAG.
Bobby, an automated accessibility checker by Watchfire, provides instant checking for both Section 508 & the WCAG. The validator first displays the page it checked without any styles applied, followed by the report. You can skip straight to the report and immediately see whether the page has passed or failed.
After the automated test result, if the website has passed the tool shows areas that can not be tested automatically, these are called User Checks and are separated for each priority in WCAG. If the page failed the automated tool, the areas that need addressing are shown, with links to examples of correct mark-up and reasoning.
However, by default, the tool validates the page to the strictest version of the WCAG, 'AAA', which may not be desired. There are some advanced options under 'customization' where you can select the level of checking. Simply, the URL contains 'AAA', which can be changed, to 'AA' and 'A', for lower levels of accessibility checking.
Cynthia Says
...is a web content accessibility validation solution, it is designed to identify errors in design related to Section 508 standards and the WCAG guidelines. The main purpose of this portal is to educate web site developers in the development Web Based content that is accessible to all.
Cynthia Says also provides instant checking for both Section 508 & the WCAG. The homepage provides a basic range of options for validation, such as checking the WCAG levels 1, 2 and 3, but defaults to the American guidelines, Section 508.
The report is a fairly complex and doesn't give a definate pass/fail like Bobby does. However, it does provide indepth information for each section of the guidelines, with links to the appropriate resources to rectify problems or to just learn more about the specific area. The checker has further options including an "Alt Text Quality" report which is also useful in accessibility checking.
Validation Tools
Probably the first step in checking a page is accessible is checking whether it's valid. There are services which can check the markup of the page against the rules of the DTD. The main validators are by the W3C, the group that defines and develops HTML and CSS.
W3C HTML Validator
Can check both URLs and local files, via upload.
W3C CSS Validator
Can check URLs, local files and by direct input. There are advanced options where you can select the profile (version), the warnings and the mediums checked.
W3C Link Checker
This tool checks all the links on the given URL but can also be configured to run through the links it finds to a certain depth.
Colorblind Web Page Filter
You can run this tool to simulate different levels of colour blindness on a web page. There are a lot of different colour filters to choose from and options such as disabling image filtering.
Assistive Technologies
There are some good tools that can be installed to help in web development and maintaining high levels of accessibility.
Browsers
Mozilla Firefox and Opera are both good alternative Windows and Mac browsers to Internet Explorer, but it is always good to check a website in as many different browsers as possible. It may also be necessary, depending on site traffic, to test your site on different versions of IE. To achieve this read the Quirks Mode's article how to run multiple versions of IE. Checking a website in numerous browsers and different platforms is impracticable for many people. Browsercam is a great tool to solve this problem.
- Mozilla Firefox - A fast and powerful web browser with download management, a popup stopper and tabbed browsing. It's extremely compliant with web standards and finally it is extensible, meaning there are hundreds of little additions which can easily be intergrated into it's function.
- Opera - An extremely powerful, highly customisable and standards complaint browser. Features a lot of tools and extras for power users including mouse gestures and a popup stopper. It also comes with integrated mail, news and chat clients. The software is adware, which means it display adverts on the browser unless paid for.
- Mozilla - A complete internet suite with browser, email client, newsgroup client, IRC chat client, and HTML editing. Based on the gecko engine which is also used on Netscape Navigator and Firefox.
Firefox Extensions
Firefox has the ability to be broadened with extensions. There are numerous extensions with are useful in web development and aid accessibility checking.
Fangs is an extension that creates a textual representation of a web page similar to how the page would be read by a modern screen reader, such as Jaws. This produces a linarized version of the page with additional informational text which is added by screen readers. However, the extension does not actually speak the page back like actual screen readers.
Web Development Toolbar is an extension full of features to aid the development of a website in general. It has quick links to validate the pages HTML, CSS and both WCAG and Section 508 via the Cynthia Says accessibility checker. The main accessibility use is the easy removal of different areas of a website such as its stylesheets, javascript, images and even page colours. There are also options to show ALT tags, accesskeys and tabindexes, highlight deprecated elements, anchors without title tags and linearize the page.
Automated Drawbacks
There are many positives to automated tools which assist checking for accessibility, such as a increased penetration to the developers, making checking for accessibility more accessible itself. However, these tools do not provide the whole picture. These tools can only catch errors and advise on them, they can not evaluate the content of the page, such as whether the ALT or title text is appropriate. The best method for ensuring best practices on websites is simple; user testing. Although this maybe unavailable, due to cost, to a lot of freelance developers it's the only way to ensure a website is fully accessible.
Automated checkers advise to add title phrases to links, however, if this text just repeats what the anchor says then this practice is more of a hindrance than a help. Accesskeys are also mentioned when researching accessible websites, however, they can be misused which generate problems in navigation and conflicts with operating system shortcuts.
Conclusion
Automated tools such as Bobby and Cynthia Says as well as assistive tools such as the web developer toolbar for Firefox help increase the basic fundamentals of building an accessible website, however, they do not replace human interaction and extensive user testing.
Further Reading & Resources
Below are resources I used for this article and would be interesting further reading on the subject.
- Web Accessibility Evaluation Tools Need People
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Web accessibility evaluation tools can be very helpful; however, they do not replace the need for human evaluation. Webster's definition of 'tool' as an 'instrument used by a craftsman or laborer at his work' is useful in understanding the role of automated web accessiblity evaluation tools.
- Web Accessibility Tools
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There is no shortage of accessibility tools on the web. The problem is identifying the ones that are really useful. Here is a collection of on-line tools that we use in our day-to-day consultancy work to support accessibility reviews.
- I'm Still Off Accesskeys
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…while there may be no explicit accessibility benefits, perhaps Accesskeys offer something for usability. Keyboard shortcuts, for those that know how to use them, can be a tremendous incremental time-saver.