Testing Accessibility

My motivation is the pursuit of perfection. Although I am aware that perfection is impossible, the strive towards perfection is not.

— Gregory Evans

• Test using Assistive Technology (AT).

  There is no substitute for testing with Assistive Technology like screen readers. The most popular screen readers are JAWS and Window Eyes.

• Test using validation tools.

  Test using the validation tools mentioned previously, but watch out for the shortcomings of validation.

• Testing using numerous browsers and other devices.

  Web sites should be accessible to everyone, including people using older browsers, handheld computers, and other devices.

• Test with different combinations of settings.
  • CSS

    Make sure the data is readable and presentable with styles disabled.

  • JavaScript

    Test with JavaScript completely or partially disabled. Check different versions of popup-blocking browsers and other tools.

  • Cookies

    If you utilize cookies to maintain session data, offer an alternative solution.

  • Images

    Test your site with images disabled in your browser. Does it still make sense? You may also want to test with a text-only browser like Lynx.

  • Color settings

    Grayscale or lower bit-depth, contrast, brightness, etc.

  • Windows IE’s unique accessibility settings

    Internet Explorer for Windows, the most popular web browser, has a truly bizarre accessibility setting. If you select Tools > Internet Options > General tab > Accessibility button, you will see three options: ignore colors, ignore font styles, and ignore font sizes. These allow a user to ignore parts (but not) all of a web page’s CSS.

    This feature was designed by developers with good intentions but it was not as well-designed as it should have been. Ignoring colors, but not positioning will negatively affect most dynamically positioned layers, such as drop-down navigation menus. A disabled person would be better off sticking with a well-crafted user style sheet.

    Despite this pitfall of design, Internet Explorer is the de facto standard web browser, and you should test with these settings anyway.

• Don’t override User CSS settings
  • Leave font-size relative to the body element.

    If you set all sub-element’s font sizes in em or percentage units, the user can adjust the entire document’s font-size with one user style on the body element.

  • Don’t Rarely use !important in author styles.

    User styles rely on being able to override author styles. If you use !important in your author styles, you make it more difficult for the user to override them. It has been brought to my attention that the previous statement does not apply to modern standards-compliant browsers. I had previously written it because of a browser bug that I can no longer verify. I think it may have been a version of Internet Explorer for Windows, but all tests now appear to work correctly.