Web Accessibility Testing

Keyboard Accessibility Testing

Definition

Keyboard-only access means that all site navigation and functionality are available using only the standard keyboard, and that the user can move freely through the page using only the standard keyboard without becoming caught in a "keyboard trap" (in which the cursor is "trapped" in one section, widget, or functional region of the document, and cannot move to another section).

Why is this an accessibility issue?

Some users find it difficult or impossible to use a mouse, often due to visual or motor impairments.  For these users, the keyboard provides a reliable means of interacting with the computer.  If the user can't operate a site with the keyboard, they can't operate it at all.

Testing Methodology

  • Access all site navigation, form controls and other functionality on a device with no mouse;
  • Determine that all content and function can be keyboard controlled;
  • Visually confirm that objects indicate focus with a visual cue;
  • Ensure that no keyboard traps exist to isolate the user in one area of the interface;
  • Review any custom key commands for conflict with the browser or operating system

Tools

  • Keyboard (View page with mouse disconnected)
    • Allows tester to tab through page to determine accessibility
  • Web Developer toolbar (CSS/View Style Information)
    • Tester can select an element and check CSS (e.g., for :focus pseudo-class) in Style Information tab
  • Web Developer toolbar (CSS/Disable Styles)
    • Reveals skip links that may be positioned off-screen

Conformance

A web site or application meets keyboard accessible criteria if:

  • All navigation and interface elements are operable through keyboard controls only;
  • Headings and focusable elements permit interface navigation for screen readers;
  • Elements change visually to indicate focus;
  • No keyboard traps are present;
  • Accessibility key commands do not conflict with key commands in the native application;
  • No other keyboard-specific barriers are present