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This is a archived version of the DMAG website, but the information remains for reference. Please visit the new website for updated information.
How to Uncover a Web Site's Accessibility Barriers
By David Sloan
Many web developers and administrators are conscious of the need to ensure that their web sites reach as high a level of accessibility as possible. But how do you actually find out whether a site has accessibility problems? Certainly, you can't assume that if no complaints have been received through the site feedback facility (assuming you have one!), there are no problems. Many people affected by accessibility problems will just give up and go somewhere else.
So you must be proactive in rooting out any problems as soon as possible. The most reliable and complete reference for assessing web accessibility is the World Wide Web Consortium's Web Content Accessiblity Guidelines 1, which come with a checklist which can be used to check pages against. Whilst a very valuable resource, the Guidelines are presented as a suite of technical documents which can be difficult to follow for many people, particularly those without much expericence in web design. Others find some guidelines excessively prescriptive, and others too vague, and checking every page againsty every guideline can take a huge amount of time.
Fortunately, there are a number of handy ways to help you get an idea of the level of accessibility of the site, which don't require an in-depth understanding of web design or accessibility issues. It may be impractical to test every page, but try to make sure you check the Home page plus as many high traffic pages as possible.
Get a disabled person to look at the site
If you have a disability, you're no doubt aware of web accessibility problems which affect you. If you know someone with a disability which might prevent them accessing information in the site, then ask them to browse the site, and tell you of any problems. Particularly affected groups include blind people (who have no functional vision and rely on audio or tactile output), people with visual impairments that affect colour perception, field of vision or readability, people with dyslexia, cognitive impairments or motor disabilities that affect manual dexterity.
If you're in UK Higher or Further Education, contact your local Access Centre 2 , who may be able to help.
View the site through a text browser
Get hold of a text browser, such as Lynx, which is available free 3, and use it to browse your site. Problems you might uncover include those caused by:
- images with no, or misleading, alternative text
- confusing navigation systems
- confusing reading order
- the use of frames without adequate help or navigation for no-frames browsing.
Browse the site using a speech browser
You can get a free evaluation version of IBM's Home Page Reader 4, a speech browser used by many visually impaired users of the Web. The browser 'speaks' the page to you, so shut your eyes and try to comprehend what you're hearing.
Alternatively, try reading a web page out loud. Ask yourself - would it make sense if you were reading it to someone who could hear you, but couldn't see the site?
Look at the site under different conditions
As suggested by the World Wide Web Consortium (W3C)'s Web Accessibility Initiative, you should test your site under various conditions to see if there are any problems:
- graphics not loaded
- frames, scripts and style sheets turned off
- browsing without using a mouse
If you use a graphical browser like Internet Explorer, Mozilla, Netscape or Opera, use your browser to change the text size - how much of the text on a page actually changes? Browsers can also be set to ignore colours, font size and style specified by pages.
Check with Automatic Validation Tools
There are a number of web based tools which can provide you with valuable information on potential accessibility problems. These include Bobby, originally from the Centre for Applied Special Technology (CAST) and now from Watchfire Inc., 5 and A-Prompt from the University of Toronto's Special needs Opportunity Window (SNOW) project 6. At the Vischeck 7 web site, you can simulate certain conditions of colourblindness, and use the site's simulation tool to view your site. You can also check whether the underlying HTML of your site validates to accepted standards using the World Wide Web Consortium's HTML Validator 8, as non-standard HTML frequently creates accessibility barriers.
Acting on Your Observations
Details of any problems found should be noted: the effect of the problem, which page was affected, plus why you think the problem was caused.
You're unlikely to catch all accessibility problems in the site, but the tests described here will give you an indication of whether the site requires immediate attention to raise accessibility. Remember that improving accessibility for specific groups, such as visually impaired people, will often have usability benefits for all users.
Commission an Accessibility Audit
Since it's unlikely you'll catch all accessibility problems and the learning curve is steep, it may be advisable to commission an expert accessibility audit. In this way, you can receive a comprehensive audit of the subject site, complete with detailed recommendations for upgrading the level of accessibility of the site. Groups who provide such audits include the Digital Media Access Group, or the RNIB, who audit web sites for access to blind users.
These are references to external web sites, for further information.
- W3C Web Content Accessibility Guidelines
- UK Access Centres
- Lynx text browser download site
- IBM Home Page Reader, evaluation version download page. A full version costs around £130.
- Bobby Home page
- Special Needs Opportunity Window (SNOW) project - from where A-Prompt can be downloaded
- Vischeck Colourblindness web site
- W3C HTML Validator