2.3.2 Meeting the guidelines for the third principle, understandable

The following are some of the points that you might want to keep in mind when creating web content and web sites that meet the Web Content Accessibility Guidelines 2.0 principle of understandable.

Level A Accessibility requirements:

  • Every web page has some method of indicating, programmatically, the language main used to write the text. In this case, language refers to the languages spoken by the users such as English, French, Spanish, Mandarin, etc. It is important for developers to provide that information so that the assistive devices and other systems can change their language automatically. Screen readers can load the correct pronunciation rules. Visual browsers can display characters and scripts correctly. Media players can show captions correctly. As a result, users with disabilities will be better able to understand the content.
  • If users interact with the organization by filling out applications or by using input forms then please ensure the following is in place.
    • All input fields or controls are clearly labelled using plain language
    • All instructions are meaningful, to the point and in plain language.
  • If the application has an error checking mechanism, then if possible include the following functions.
    • Ensure that the error checking mechanism notes and describes any errors in the text.
    • Ensure that the error checking mechanism indicates that there has been an error at the point at which the error has occurred so that the user can find it easily and make the necessary corrections. This would not preclude collecting all the errors on a page and listing the material the top of the page. Refer also to Example 1 on the next page.
  • Never cause an object receiving focus to cause a substantial change in context without warning
    • e.g., some "roll-over" events cause additional helper information to appear somewhere on the display — A keyboard user tabs through a web page with complex terms. When the user tabs over a complex term a dialogue box launches without 'activation' to explain the concept, moving the keyboard focus away from the control every time the user attempts to tab past the field.
  • Provide warning to users if an action (event) triggered in one page location causes a change in another page location (which may not be detectable by the user or their assistive devices).
    • e.g., selecting different options from a questionnaire form causes a different set follow-up questions to appear.

Level AA Accessibility Requirements:

  • Provide users with suggestions when errors are made. Refer also to Example 2 below.
  • Every phrase or passage within the web page — with specific exceptions — has some method of indicating, programmatically, the human language (e.g. English, French, Spanish, etc.). For example, the web page may be in English, but if the author has used the French phrase "raison d'être", you should indicate a change in the human language. Refer also to Example 3 on the next page.
  • Navigation mechanisms that are repeated on numerous pages — like the navigation bar often found on the left side of a web page — should always occur in the same relative order. You must also be consistent when using components that have the same functionality. For example, you wouldn't want to title your search component on the website "search" on one page and "find" on another.
  • If users are submitting information that causes a legal or financial commitment; changes their user-controllable stored data or test responses, then make it so the transaction can be reversed OR data is checked for input errors, OR the user can confirm before submitting.