Keyboard accessibility principles

Website accessibility via the keyboard is one of the most important aspects of disability access. Keyboard accessibility is important to people with the following disabilities:

• Blindness
• Low vision
• Motor impairments
• Cognitive impairments

It is commonly known that websites are often accessed using the mouse. However, for many users, the use of the keyboard can increase their ability to navigate and access the content and functionality of a web page effectively. Some users will rely on their keyboard exclusively. Individual use and combinations of keys such as the ‘TAB’, ‘Ctrl’, ‘Shift’, ‘Enter’ and arrow keys are used, sometimes in conjunction with the use of other assistive technologies such as screen readers.

Areas of importance for keyboard access are also covered specifically in the relevant category factsheets:

• Navigation Use of main and sub navigation with and without the use of JavaScript.
• Content Accessing links and moving around the page, avoiding reference to device-dependent handlers within page content or feature instructions.
• Coding Controlling moving or scrolling content.
• Forms Entering, validating and submitting information.
• Interactive site features Using Interactive maps and Image maps; Slideshows; Image galleries; Virtual tours; Magazines; Calendars; Flash or JavaScript features and Java applets; Audio/Video and any other interactive object.

Accessibility principles specific to the use of the keyboard include, but are not limited to:

• Avoid keyboard traps
  • When a keyboard user encounters a keyboard trap and is therefore unable to exit a site feature or content area they are effectively stuck and must close the browser window and start again. If all content, controls and interactive elements cannot be accessed and/or operated via the keyboard, users that rely on the keyboard alone will be unable to navigate or understand the site.
• Ensure that all content can be accessed with the keyboard alone
  • Do not prevent keyboard users from accessing any website content or functionality.
  • Ensure that standard keyboard shortcuts are operable and that the navigation can be accessed through standard means.
  • Avoid referring to device-dependent handlers (e.g. “click”) within page content or instructional text.
• Keyboard focus indicator is highly visible and clear
  • Do not remove visible keyboard focus indicators on any items i.e. links, navigation, form fields, buttons or any other object control.
• Ensure that all information is available via the keyboard
  • Avoid the use of the TITLE attribute on links and images as this information cannot be accessed by the keyboard.
  • Ensure that all content appears on keyboard focus in a way which is consistent with content appearing on mouse over e.g. tool tips.
• Item presentation changes on keyboard focus
  • Item presentation should change when keyboard focus is received in the same way as when a mouse hovers over the content.