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The Pros and Cons of Access Keys
By Leona Westland, published 9th March 2004.
Introduction
Endorsed by the World Wide Web Consortium (W3C) [1], the HTML accesskey attribute is intended to improve web interaction for users navigating without a pointing device, such as a mouse. Access keys provide web developers with a means of specifying a keyboard shortcut for moving to a link, form component or other tabbable object, using the following HTML elements - a, area, button, input, label, legend or textarea.
For instance, we can assign the character "C" to the link for a "Contact us" page using the following HTML code:
<a accesskey="C" href="contact_us.asp" hreflang="en" title="Contact Us Page">Contact Us Page</a>
Users can take advantage of access keys by using this character as part of a key combination, although this varies according to the underlying operating system. Windows users would press Alt + C to navigate to the Contact Us Page, whilst Mac users would press CTRL + C.
Keyboard shortcuts are a feature of user-centred software design, so in principle, the accesskey attribute offers great potential for improving web interaction for:
- people with physical dexterity impairments that mean they are unable to use a mouse.
- blind people, who cannot use a mouse and may particularly benefit from enhanced keyboard control.
- users of any browsing device that does not have a pointing device.
- any user who finds keyboard shortcuts a preferable way of controlling software.
Pitfalls
However, since their introduction by the W3C, there has been much debate about the practicalities [2].
It is highly likely that the accesskeys specified on a site will conflict with keyboard commands already in use by some browsers or assistive technologies. Where accesskeys take precedence over identical browser keyboard shortcuts, this may particularly lead to important browser functionality no longer working. Research suggested that there were only three possible keyboard shortcuts that would not conflict with browser or assistive technology functionality [3].
Some browsers still do not support accesskeys, and for those that do, support for the accesskey attribute is inconsistent:
- In interpretation of accesskeys, resulting in lack of consistency in an action required to initiate them - since many people are unaware of the concept of accesskeys, this making writing instructions for their usage even more complex than necessary.
- In terms of how the user is notified of the presence of an accesskey. A lack of specification for this means that browsers do not provide this information automatically, so a textual listing is required of all keyboard shortcuts somewhere on the site.
Again, this leaves the decision up to the developer of the web site, which promotes a lack of consistency across the Web. Using a letter corresponding to the destination page title or button functionality may seem intuitive, but can lead to internationalisation problems as well as obvious issues where two links on the same page may seem to have equal claim for the same accesskey.
Conclusions and Recommendations
Although accesskeys may eventually allow improved keyboard accessibility and usability of web sites, browser implementation and consistency issues in the current environment leaves a lot to be desired. It is highly likely that whatever implementation method is used, a subset of users will find them problematic where the access keys conflict with their browser or assistive technology's shortcut keys.
At the current point in time, accesskeys should therefore be seen as a relatively low priority accessibility feature [4]. However, their use may be valuable particularly to aid navigation through complex forms, or in a controlled environment such as an on-line game.
Whilst there is no current unified convention, general advice - e.g. [5] - recommends usage of numbers rather than letters as accesskey mappings to limit potential conflicts with browsing technology. Some organisations have specified accesskey mappings, for example the Office of the E-Envoy in clued accesskey recommendations in their Guidelines for UK Government web sites [6]
References and Reading
- WCAG Checkpoint 9.5: Provide keyboard shortcuts to important links, form controls and groups of form controls (http://www.w3.org/TR/WAI-WEBCONTENT-TECHS/#tech-keyboard-shortcuts)
- Robertson, S (2003): Accesskeys: Unlocking Hidden Navigation. In A List Apart #158: http://www.alistapart.com/articles/accesskeys/
- AccessKeys and Reserved Keystroke combinations: http://www.wats.ca/resources/accesskeysandkeystrokes/38
- Using Access Keys - Is it worth it? http://www.wats.ca/resources/accesskeys/19
- Korpela, J (2003): Improving accessibility with accesskey in HTML forms and links http://www.cs.tut.fi/~jkorpela/forms/accesskey.html
- Guidelines for UK Government web sites: http://www.e-envoy.gov.uk/Resources/WebGuidelines/fs/en