HTML and CSS Reference
Table C-1 (continued)
WCAG 2.0 Guidelines
3.1.3 Unusual Words: A mechanism is available for identifying specific definitions of words or
phrases used in an unusual or restricted way, including idioms and jargon.
3.1.4 Abbreviations: A mechanism for identifying the expanded form or meaning of
abbreviations is available.
3.1.5 Reading Level: When text requires reading ability more advanced than the lower secondary
education level after removal of proper names and titles, supplemental content, or a version that
does not require reading ability more advanced than the lower secondary education level, is available.
3.1.6 Pronunciation: A mechanism is available for identifying specific pronunciation of words
where the meaning of the words, in context, is ambiguous without knowing the pronunciation.
Guideline 3.2 Predictable: Make Web pages appear and operate in predictable ways.
3.2.1 On Focus: When any component receives focus, it does not initiate a change of context.
3.2.2 On Input: Changing the setting of any user interface component does not automatically
cause a change of context unless the user has been advised of the behavior before using the
3.2.3 Consistent Navigation: Navigational mechanisms that are repeated on multiple
Web pages within a set of Web pages occur in the same relative order each time they
are repeated, unless a change is initiated by the user.
3.2.4 Consistent Identification: Components that have the same functionality within a
set of Web pages are identified consistently.
3.2.5 Change on Request: Changes of context are initiated only by user request or a
mechanism is available to turn off such changes.
Guideline 3.3 Input Assistance: Help users avoid and correct mistakes.
3.3.1 Error Identification: If an input error is automatically detected, the item that is in
error is identified and the error is described to the user in text.
3.3.2 Labels or Instructions: Labels or instructions are provided when content requires user input.
3.3.3 Error Suggestion: If an input error is automatically detected and suggestions for its
correction are known, then the suggestions are provided to the user, unless it would jeopardize
the security or purpose of the content.
3.3.4 Error Prevention (Legal, Financial, Data): For Web pages that cause legal
commitments or financial transactions for the user to occur, that modify or delete user-
controllable data in data storage systems, or that submit user test responses, a mechanism is
available for reviewing, confirming, and correcting information before finalizing the submission.
3.3.5 Help: Context-sensitive help is available.
3.3.6 Error Prevention (All): For Web pages that require the user to submit information, a
mechanism is available for reviewing, confirming, and correcting information before finalizing
Principle 4: Robust—Content must be robust enough that it can be interpreted reliably
by a wide variety of user agents, including assistive technologies.
Guideline 4.1 Compatible: Maximize compatibility with current and future user agents,
including assistive technologies.
4.1.1 Parsing: In content implemented using markup languages, elements have complete start
and end tags, elements are nested according to their specifications, elements do not contain
duplicate attributes, and any IDs are unique, except where the specifications allow these features.
4.1.2 Name, Role, Value: For all user interface components (including but not limited to:
form elements, links, and components generated by scripts), the name and role can be
programmatically determined; states, properties, and values that can be set by the user can be
programmatically set; and notification of changes to these items is available to user agents,
including assistive technologies.