Web Accessibility Principles and Guidelines from WCAG

We have duplicated the Web Content Accessibility Guidelines (WCAG) principles and guidelines to integrate additional resource links as they are associated to each. The primary links will lead you to the full descriptions from the W3C, while resource links are displayed below the guidelines.

WCAG Levels: In order to determine the depth that each site complies with the guidelines, they developed three grade levels (A, AA, AAA). Each of the guidelines associates its compliance to one of the levels. Level A consists of foundational guidelines that at a minimum all web sites should meet. Level AA is harder to meet than Level A, but is the defacto achievement Level required by OCR. Level AAA is much harder to achieve - on larger sites, most agree it is not likely attainable. An example comparison for the levels could be found in Color Contrast... where Level A could be a blue background with yellow text, a Level AA could be a blue background with white text, and Level AAA could be a black background with white text.
National Center on Accessible Educational Materials: The AEM site shows a pretty simplified explanation of the POUR principle.

Principle 1: Perceivable

Information and user interface components must be presentable to users in ways they can perceive.

Guideline 1.1: Text Alternatives: All non-text content that is presented to the user has a text alternative that serves the equivalent purpose, except for the situations listed at the WCAG description.
1.1.1 Non-text Content: All non-text content that is presented to the user has a text alternative that serves the equivalent purpose.
(Level) A Targets: AWG Developer FileMaker
Guideline 1.2: Time-based Media: Provide alternatives for time-based media.
1.2.1 Audio-only and Video-only (Prerecorded): For prerecorded audio-only and prerecorded video-only media, the following are true, except when the audio or video is a media alternative for text and is clearly labeled as such.
(Level) A Targets: VideoMaker AudioOnlyMaker
1.2.2 Captions (Prerecorded): Captions are provided for all prerecorded audio content in synchronized media, except when the media is a media alternative for text and is clearly labeled as such.
(Level) A Targets: VideoMaker AudioOnlyMaker
1.2.3 Audio Description or Media Alternative (Prerecorded): An alternative for time-based media or audio description of the prerecorded video content is provided for synchronized media, except when the media is a media alternative for text and is clearly labeled as such.
(Level) A Targets: VideoMaker AudioOnlyMaker
1.2.4 Captions (Live): Captions are provided for all live audio content in synchronized media.
(Level) AA Targets: VideoMaker
1.2.5 Audio Description (Prerecorded): Audio description is provided for all prerecorded video content in synchronized media.
(Level) AA Targets: VideoMaker
1.2.6 Sign Language (Prerecorded): Sign language interpretation is provided for all prerecorded audio content in synchronized media.
(Level) AAA Targets: VideoMaker
1.2.7 Extended Audio Description (Prerecorded): Where pauses in foreground audio are insufficient to allow audio descriptions to convey the sense of the video, extended audio description is provided for all prerecorded video content in synchronized media.
(Level) AAA Targets: VideoMaker
1.2.8 Media Alternative (Prerecorded): An alternative for time-based media is provided for all prerecorded synchronized media and for all prerecorded video-only media.
(Level) AAA Targets: VideoMaker
1.2.9 Audio-only (Live): An alternative for time-based media that presents equivalent information for live audio-only content is provided.
(Level) AAA Targets: AudioOnlyMaker
Guideline 1.3: Adaptable: Create content that can be presented in different ways (for example simpler layout) without losing information or structure.
1.3.1 Info and Relationships: Information, structure, and relationships conveyed through presentation can be programmatically determined or are available in text.
(Level) A Targets: AWG Developer PageMaker FileMaker
1.3.2 Meaningful Sequence: When the sequence in which content is presented affects its meaning, a correct reading sequence can be programmatically determined.
(Level) A Targets: AWG Developer FileMaker
1.3.3 Sensory Characteristics: Instructions provided for understanding and operating content do not rely solely on sensory characteristics of components such as shape, size, visual location, orientation, or sound.
(Level) A Targets: AWG Developer PageMaker FileMaker
Guideline 1.4: Distinguishable: Make it easier for users to see and hear content including separating foreground from background.
1.4.1 Use of Color: Color is not used as the only visual means of conveying information, indicating an action, prompting a response, or distinguishing a visual element.
(Level) A Targets: AWG Developer PageMaker FileMaker
1.4.2 Audio Control: If any audio on a Web page plays automatically for more than 3 seconds, either a mechanism is available to pause or stop the audio, or a mechanism is available to control audio volume independently from the overall system volume level.
(Level) A Targets: AWG PageMaker
1.4.3 Contrast (Minimum): The visual presentation of text and images of text has a contrast ratio of at least 4.5:1, except in some instances.
(Level) AA Targets: AWG Developer PageMaker FileMaker
1.4.4 Resize text: Except for captions and images of text, text can be resized without assistive technology up to 200 percent without loss of content or functionality.
(Level) AA Targets: Developer
1.4.5 Images of Text: If the technologies being used can achieve the visual presentation, text is used to convey information rather than images of text except in some instances.
(Level) AA Targets: AWG Developer PageMaker FileMaker
1.4.6 Contrast (Enhanced): The visual presentation of text and images of text has a contrast ratio of at least 7:1, except in some instances.
(Level) AAA Targets:
1.4.7 Low or No Background Audio: For prerecorded audio-only content that (1) contains primarily speech in the foreground, (2) is not an audio CAPTCHA or audio logo, and (3) is not vocalization intended to be primarily musical expression such as singing or rapping.
(Level) AAA Targets: AudioOnlyMaker
1.4.8 Visual Presentation: For the visual presentation of blocks of text.
(Level) AAA Targets:
1.4.9 Images of Text (No Exception): Images of text are only used for pure decoration or where a particular presentation of text is essential to the information being conveyed.
(Level) AAA Targets:

Principle 2: Operable

User interface components and navigation must be operable.

Guideline 2.1: Keyboard Accessible: Make all functionality available from a keyboard.
2.1.1 Keyboard: All functionality of the content is operable through a keyboard interface without requiring specific timings for individual keystrokes, except where the underlying function requires input that depends on the path of the user's movement and not just the endpoints.
(Level) A Targets: Developer
2.1.2 No Keyboard Trap: If keyboard focus can be moved to a component of the page using a keyboard interface, then focus can be moved away from that component using only a keyboard interface, and, if it requires more than unmodified arrow or tab keys or other standard exit methods, the user is advised of the method for moving focus away.
(Level) A Targets: Developer
2.1.3 Keyboard (No Exception): All functionality of the content is operable through a keyboard interface without requiring specific timings for individual keystrokes.
(Level) AAA Targets:
Guideline 2.2: Enough Time: Provide users enough time to read and use content.
2.2.1 Timing Adjustable: For each time limit that is set by the content.
(Level) A Targets: AWG Developer PageMaker
2.2.2 Pause, Stop, Hide: For moving, blinking, scrolling, or auto-updating information.
(Level) A Targets: Developer
2.2.3 No Timing: Timing is not an essential part of the event or activity presented by the content, except for non-interactive synchronized media and real-time events.
(Level) AAA Targets:
2.2.4 Interruptions: Interruptions can be postponed or suppressed by the user, except interruptions involving an emergency.
(Level) AAA Targets:
2.2.5 Re-authenticating: When an authenticated session expires, the user can continue the activity without loss of data after re-authenticating.
(Level) AAA Targets:
Guideline 2.3: Seizures and Physical Reactions: Do not design content in a way that is known to cause seizures or physical reactions.
2.3.1 Three Flashes or Below Threshold: Web pages do not contain anything that flashes more than three times in any one second period, or the flash is below the general flash and red flash thresholds.
(Level) A Targets: AWG Developer PageMaker FileMaker
2.3.2 Three Flashes: Web pages do not contain anything that flashes more than three times in any one second period.
(Level) AAA Targets:
Guideline 2.4: Navigable: Provide ways to help users navigate, find content, and determine where they are.
2.4.1 Bypass Blocks: A mechanism is available to bypass blocks of content that are repeated on multiple Web pages.
(Level) A Targets: Developer
2.4.2 Page Titled: Web pages have titles that describe topic or purpose.
(Level) A Targets: AWG Developer PageMaker FileMaker
2.4.3 Focus Order: If a Web page can be navigated sequentially and the navigation sequences affect meaning or operation, focusable components receive focus in an order that preserves meaning and operability.
(Level) A Targets: Developer
2.4.4 Link Purpose (In Context): The purpose of each link can be determined from the link text alone or from the link text together with its programmatically determined link context, except where the purpose of the link would be ambiguous to users in general.
(Level) A Targets: AWG Developer
2.4.5 Multiple Ways: More than one way is available to locate a Web page within a set of Web pages except where the Web Page is the result of, or a step in, a process.
(Level) AA Targets: Developer
2.4.6 Headings and Labels: More than one way is available to locate a Web page within a set of Web pages except where the Web Page is the result of, or a step in, a process.
(Level) AA Targets: Developer
2.4.7 Focus Visible: Any keyboard operable user interface has a mode of operation where the keyboard focus indicator is visible.
(Level) AA Targets: Developer
2.4.8 Location: Information about the user's location within a set of Web pages is available.
(Level) AAA Targets:
2.4.9 Link Purpose (Link Only): A mechanism is available to allow the purpose of each link to be identified from link text alone, except where the purpose of the link would be ambiguous to users in general.
(Level) AAA Targets:
2.4.10 Section Headings: Section headings are used to organize the content.
(Level) AAA Targets:

Principle 3: Understandable

Information and the operation of user interface must be understandable.

Guideline 3.1: Readable: Make text content readable and understandable.
3.1.1 Language of Page: The default human language of each Web page can be programmatically determined.
(Level) A Targets: AWG Developer PageMaker
3.1.2 Language of Parts: The human language of each passage or phrase in the content can be programmatically determined except for proper names, technical terms, words of indeterminate language, and words or phrases that have become part of the vernacular of the immediately surrounding text.
(Level) AA Targets: AWG Developer PageMaker
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.
(Level) AAA Targets:
3.1.4 Abbreviations: A mechanism for identifying the expanded form or meaning of abbreviations is available.
(Level) AAA Targets:
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.
(Level) AAA Targets:
3.1.6 Pronunciation: A mechanism is available for identifying specific pronunciation of words where meaning of the words, in context, is ambiguous without knowing the pronunciation.
(Level) AAA Targets:
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.
(Level) A Targets: Developer
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 component.
(Level) A Targets: Developer
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.
(Level) AA Targets: Developer
3.2.4 Consistent Identification: Components that have the same functionality within a set of Web pages are identified consistently.
(Level) AA Targets: Developer
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.
(Level) AAA Targets:
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.
(Level) A Targets: Developer
3.3.2 Labels or Instructions: Labels or instructions are provided when content requires user input.
(Level) A Targets: Developer
3.3.3 Error Suggestion: If an input error is automatically detected and suggestions for correction are known, then the suggestions are provided to the user, unless it would jeopardize the security or purpose of the content.
(Level) AA Targets: Developer
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.
(Level) AA Targets: Developer
3.3.5 Help: Context-sensitive help is available.
(Level) AAA Targets:
3.3.6 Error Prevention (All): For Web pages that require the user to submit information.
(Level) AAA Targets:

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.
(Level) A Targets: Developer
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.
(Level) A Targets: Developer