Accessibility Support Documentation for PDF

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, except for the situations listed below. (Level A)

• Controls, Input: If non-text content is a control or accepts user input, then it has a name that describes its purpose. (Refer to Guideline 4.1 for additional requirements for controls and content that accepts user input.)
• Time-Based Media: If non-text content is time-based media, then text alternatives at least provide descriptive identification of the non-text content. (Refer to Guideline 1.2 for additional requirements for media.)
• Test: If non-text content is a test or exercise that would be invalid if presented in text, then text alternatives at least provide descriptive identification of the non-text content.
• Sensory: If non-text content is primarily intended to create a specific sensory experience, then text alternatives at least provide descriptive identification of the non-text content.
• CAPTCHA: If the purpose non-text content is to confirm that content is being accessed by a person rather than a computer, then text alternatives that identify and describe the purpose of the non-text content are provided, and alternative forms of CAPTCHA using output modes for different types of sensory perception are provided to accommodate different disabilities.
• Decoration, Formatting, Invisible: If non-text content is pure decoration, is used only for visual formatting, or is not presented to users, then it is implemented in a way that it can be ignored by assistive technology.

The PDF specification provides ways to include equivalents for images, as detailed in section 14.9.3 of the ISO 32000-1 PDF specification.

Test results:

• Test id 1 (Image eqivalents)
• Test id 2 (Decorative images)
• Test id 3 (Controls, Input labels)

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)

• Prerecorded Audio-only: An alternative for time-based media is provided that presents equivalent information for prerecorded audio-only content.
• Prerecorded Video-only: Either an alternative for time-based media or an audio track is provided that presents equivalent information for prerecorded video-only content.

No Accessibility Support impact.

Not applicable to PDF format.  Applies to media embedded within PDF documents.

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)

No Accessibility Support impact.

Not applicable to PDF format.  Applies to media embedded within PDF documents.

1.2.3 Audio Description or Media Alternative: 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)

No Accessibility Support impact.

Not applicable to PDF format.  Applies to media embedded within PDF documents.

1.2.4 Captions (Live): Captions are provided for all live audio content in synchronized media. (Level AA)

No Accessibility Support impact.

Not applicable to PDF format.  Applies to media embedded within PDF documents.

1.2.5 Audio Description: Audio description is provided for all prerecorded video content in synchronized media. (Level AA)

No Accessibility Support impact.

Not applicable to PDF format.  Applies to media embedded within PDF documents.

1.2.6 Sign Language: Sign language interpretation is provided for all prerecorded audio content in synchronized media. (Level AAA)

No Accessibility Support impact.

Not applicable to PDF format.  Applies to media embedded within PDF documents.

1.2.7 Audio Description (Extended): 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)

No Accessibility Support impact.

Not applicable to PDF format.  Applies to media embedded within PDF documents.

1.2.8 Media Alternative: An alternative for time-based media is provided for all prerecorded synchronized media and for all prerecorded video-only media. (Level AAA)

No Accessibility Support impact.

Not applicable to PDF format.  Applies to media embedded within PDF documents.

A media alternative may be included within a PDF document that contains qualifying media or the alternative may be contained in a separate PDF file or other accessible format.

1.2.9 Live Audio-only: A An alternative for time-based media that presents equivalent information for live audio-only content is provided. (Level AAA)

No Accessibility Support impact.

Not applicable to PDF format.  Applies to media embedded within PDF documents.

1.3.1 Info and Relationships: Information, structure, and relationships conveyed through presentation can be programmatically determined or are available in text. (Level A)

PDF provides a variety of ways to convey information and relationships with semantic elements such as headings, lists, tables, and paragraphs. The ISO 32000-1 PDF Specification details structure types in section 14.8.4.

Test results:

• Test id 4 (Correctly tagged paragraphs)
• Test id 5 (Correctly tagged headings)
• Test id 6(Correctly tagged controls and input elements)

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)

PDF supports a defined programmatic order to content. The ISO 32000-1 PDF Specification details PDF page content order in seciton 14.8.2.3.

Test results:

• Test id 7 (PDF with logical order)
• Test id 8 (PDF with multiple columns of text)

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)

Note: For requirements related to color, refer to Guideline 1.4.

No Accessibility Support impact.

This is design-specific and can be met by avoiding instructions such as "click the red button". 

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)

Note: This success criterion addresses color perception specifically. Other forms of perception are covered in Guideline 1.3 including programmatic access to color and other visual presentation coding.

No Accessibility Support impact.

This is design-specific.  Application or document authors need to consider this provision and ensure conformance.

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)

Note: Since any content that does not meet this success criterion can interfere with a user's ability to use the whole page, all content on the Web page (whether or not it is used to meet other success criteria) must meet this success criterion. See Conformance Requirement 5: Non-Interference.

No Accessibility Support impact.

Uninterruptible audio can be avoided or a mechanism can be provided to silence it. This relates more directly to embedded media players within a PDF document.

1.4.3 Contrast (Minimum): The visual presentation of text and images of text has a contrast ratio of at least 5:1, except for the following: (Level AA)

• Large Text: Large-scale text and images of large-scale text have a contrast ratio of at least 3:1;
• Incidental: Text or images of text that are part of an inactive user interface component, that are pure decoration, that are not visible to anyone, or that are part of a picture that contains significant other visual content, have no contrast requirement.
• Logotypes: Text that is part of a logo or brand name has no minimum contrast requirement.

No Accessibility Support impact.

This is design-specific.  Application or document authors need to consider this provision and ensure conformance.

Adobe Reader provides functionality that allows for alternative and high-contrast views of documents either by selecting a predefined color setting or by mirroring the OS settings.

The built in contrast tool in Adobe Reader does not adjust the background color for regions within a page, only the primary background, so authors may need to avoid using regions or carefully check color contrast possibilities for these areas.

1.4.4 Resize text: Text (but not images of text) can be resized without assistive technology up to 200 percent without loss of content or functionality. (Level AA)

Adobe Reader provides a zooming feature for text.

[G142: Using a technology that has commonly-available user agents that support zoom]

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 for the following: (Level AA)

• Customizable: The image of text can be visually customized to the user's requirements;
• Essential: A particular presentation of text is essential to the information being conveyed.

Note: Logotypes (text that is part of a logo or brand name) are considered essential.

No Accessibility Support impact. This is design-specific. Application or document authors need to consider this provision and ensure conformance.

PDF provides a way to provide an equivalent for images of text, but it is at the author’s discretion as to whether to incorporate text or images of text in order to conform with this success criteria.

1.4.6 Contrast (Enhanced): The visual presentation of text and images of text has a contrast ratio of at least 7:1, except for the following: (Level AAA)

• Large Text: Large-scale text and images of large-scale text have a contrast ratio of at least 5:1;
• Incidental: Text or images of text that are part of an inactive user interface component, that are pure decoration, that are not visible to anyone, or that are part of a picture that contains significant other visual content, have no contrast requirement.
• Logotypes: Text that is part of a logo or brand name has no minimum contrast requirement.

No Accessibility Support impact.

This is design-specific.  Application or document authors need to consider this provision and ensure conformance.

Adobe Reader provides functionality that allows for alternative and high-contrast views of documents either by selecting a predefined color setting or by mirroring the OS settings.

The built in contrast tool in Adobe Reader does not adjust the background color for regions within a page, only the primary background, so authors may need to avoid using regions or carefully check color contrast possibilities for these areas.

1.4.7 Low or No Background Audio: For audio content that (1) is not an audio CAPTCHA and (2) contains speech in the foreground, at least one of the following is true: (Level AAA)

• No Background: The audio does not contain background sounds.
• Turn Off: The background sounds can be turned off.
• 20 dB: The background sounds are at least 20 decibels lower than the foreground speech content, with the exception of occasional sound effects.

Note 1: Per the definition of "decibel," background sound that meets this requirement will be approximately four times quieter than the foreground speech content.

Note 2: Given that in normal speech, hearing people loose the occasional word, it is acceptable to have occasional dips of contrast between 10dBs-20dBs for up to 2 words in a sentence that are isolated and not nouns or verbs.

No Accessibility Support impact.

Background audio can be avoided or a mechanism can be provided to silence it. Otherwise, conformance with this success criteria depends on accurate identification of audio levels and keeping the audio level sufficiently low.

1.4.8 Visual Presentation: For the visual presentation of blocks of text, a mechanism is available to achieve the following: (Level AAA)

• foreground and background colors can be selected by the user
• width is no more than 80 characters or glyphs (40 if CJK)
• text is not justified (aligned to both the left and the right margins)
• line spacing (leading) is at least space-and-a-half within paragraphs, and paragraph spacing is at least 1.5 times larger than the line spacing
• text can be resized without assistive technology up to 200 percent in a way that does not require the user to scroll horizontally to read a line of text on a full-screen window

Foreground and background colors: Adobe Reader allows users to select foreground and background colors for the primary page background and text foreground.

Width: Adobe Reader allows users to reflow tagged PDF files and zoom in on the content or resize the window to achieve a width of no more than 40 characters.The ISO 32000-1 PDF Specification details document reflow in PDF in section 14.8.2.3.

Text justification: Justified text  can be disabled by enabling text reflow in Adobe Reader.

Line spacing: Line spacing is dependent on authors defining appropriate line and paragraph spacing.

Text resizing: Adobe Reader’s zoom feature provides over 200% zoom and the reflow feature allows text to not require horizontal scrolling.

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)

Note: Logotypes (text that is part of a logo or brand name) are considered essential.

No Accessibility Support impact. 

This is design-specific. Application or document authors need to consider this provision and ensure conformance.

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)

Note 1: This exception relates to the underlying function, not the input technique. For example, if using handwriting to enter text, the input technique (handwriting) requires path dependent input but the underlying function (text input) does not.

Note 2: This does not forbid and should not discourage providing mouse input or other input methods in addition to keyboard operation.

PDF forms and other interactive elements are operable through a keyboard interface without requiring specific timing.

The ISO 32000-1 PDF Specification details form fields in section 12.7.4.1.

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)

Note: Since any content that does not meet this success criterion can interfere with a user's ability to use the whole page, all content on the Web page (whether it is used to meet other success criteria or not) must meet this success criterion. See Conformance Requirement 5: Non-Interference.

Authors who design PDF forms and utilize scripting need to test to ensure that keyboard traps are not created when moving from control to control.

Form controls created by Adobe Acrobat PDF files do not provide a keyboard trap.

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)

PDF forms do not require specific timing for keyboard access to standard controls. 

2.2.1 Timing Adjustable: For each time limit that is set by the content, at least one of the following is true: (Level A)

• Turn off: The user is allowed to turn off the time limit before encountering it; or
• Adjust: The user is allowed to adjust the time limit before encountering it over a wide range that is at least ten times the length of the default setting; or
• Extend: The user is warned before time expires and given at least 20 seconds to extend the time limit with a simple action (for example, "press the space bar"), and the user is allowed to extend the time limit at least ten times; or
• Real-time Exception: The time limit is a required part of a real-time event (for example, an auction), and no alternative to the time limit is possible; or
• Essential Exception: The time limit is essential and extending it would invalidate the activity; or
• 20 Hour Exception: The time limit is longer than 20 hours.

Note 1: This success criterion helps ensure that users can complete tasks without unexpected changes in content or context that are a result of a time limit. This success criterion should be considered in conjunction with Success Criterion 3.2.1 which puts limits on changes of content or context as a result of user action.

No Accessibility Support impact. This is design-specific. Application or document authors need to consider this provision and ensure conformance.

PDF forms do not require specific timing for keyboard access to standard controls. 

2.2.2 Pause, Stop, Hide: For moving, blinking, scrolling, or auto-updating information, all of the following are true: (Level A)

• Moving, blinking, scrolling: For any moving, blinking or scrolling information that (1) starts automatically, (2) lasts more than five seconds, and (3) is presented in parallel with other content, there is a mechanism for the user to pause, stop, or hide it unless the movement, blinking, or scrolling is part of an activity where it is essential; and
• Auto-updating: For any auto-updating information that (1) starts automatically and (2) is presented in parallel with other content, there is a mechanism for the user to pause, stop, or hide it or to control the frequency of the update unless the auto-updating is part of an activity where it is essential.

Note 1: For requirements related to flickering or flashing content, refer to Guideline 2.3.

Note 2: Since any content that does not meet this success criterion can interfere with a user's ability to use the whole page, all content on the Web page (whether it is used to meet other success criteria or not) must meet this success criterion. See Conformance Requirement 5: Non-Interference.

Note 3: Content that is updated periodically by software, or that is streamed to the user agent is not required to preserve or present information that is generated or received between the initiation of the pause and resuming presentation, as this may not be technically possible, and in many situations could be misleading to do so.

Note 4: An animation that occurs as part of a preload phase or similar situation can be considered essential if interaction cannot occur during that phase for all users, and if not indicating progress could confuse users or cause them to think that content was frozen or broken.

No Accessibility Support impact. This is design-specific. Application or document authors need to consider this provision and ensure conformance.

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)

No Accessibility Support impact. This is design-specific. Application or document authors need to consider this provision and ensure conformance.

2.2.4 Interruptions: Interruptions can be postponed or suppressed by the user, except interruptions involving an emergency. (Level AAA)

No Accessibility Support impact. This is design-specific. Application or document authors need to consider this provision and ensure conformance.

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)

No Accessibility Support impact. This is design-specific. Application or document authors need to consider this provision and ensure conformance.

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)

Note: Since any content that does not meet this success criterion can interfere with a user's ability to use the whole page, all content on the Web page (whether it is used to meet other success criteria or not) must meet this success criterion. See Conformance Requirement 5: Non-Interference.

No Accessibility Support impact. This is design-specific. Application or document authors need to consider this provision and ensure conformance.

This is an author consideration for embedded media in PDF.

2.3.2 Three Flashes: Web pages do not contain anything that flashes more than three times in any one second period. (Level AAA)

No Accessibility Support impact. This is design-specific. Application or document authors need to consider this provision and ensure conformance.

2.4.1 Bypass Blocks: A mechanism is available to bypass blocks of content that are repeated on multiple Web pages. (Level A)

PDF allows documents to be tagged with headings which can be used in conjunction with assistive technologies to bypass sections of content.  PDF also provides bookmarking functionality that allows keyboard users to accomplish similar bypassing.

Test results:

• Test id 9 (Correctly tagged headings)
• Test id 10 (PDF bookmarks)

2.4.2 Page Titled: Web pages have titles that describe topic or purpose. (Level A)

PDF allows documents to be titled. The ISO 32000-1 PDF Specification details document titles in section 14.1.

Test results:

• Test id 11 (PDF document with Title)

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)

PDF provides the ability for authors to control the tab and reading order.

Test results:

• Test id 12 (PDF form with correct tab order)
• Test id 13 (PDF form with incorrect tab order)

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)

No Accessibility Support impact. This is design-specific. Application or document authors need to consider this provision and ensure conformance.

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)

No Accessibility Support impact. This is design-specific. Application or document authors need to consider this provision and ensure conformance.

2.4.6 Headings and Labels: Headings and labels describe topic or purpose. (Level AA)

No Accessibility Support impact. This is design-specific. Application or document authors need to consider this provision and ensure conformance.

2.4.7 Focus Visible: Any keyboard operable user interface has a mode of operation where the keyboard focus indicator is visible. (Level AA)

Adobe Reader provides a visible keyboard focus.

Test results:

• Test id 14 (PDF with visible focus)

2.4.8 Location: Information about the user's location within a set of Web pages is available. (Level AAA)

Adobe Reader provides information about page numbering within PDF documents as part of the Adobe Reader user interface.

Test results:

Test id 15 (PDF with 100 pages, showing page numbering in UI)

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)

No Accessibility Support impact.

This is design-specific.  Application or document authors need to consider this provision and ensure conformance.

2.4.10 Section Headings: Section headings are used to organize the content. (Level AAA)

Note 1: "Heading" is used in its general sense and includes titles and other ways to add a heading to different types of content.

Note 2: This success criterion covers sections within writing, not user interface components. User Interface components are covered under Success Criterion 4.1.2.

PDF provides support for headings to convey content organization. The ISO 32000-1 PDF Specification details the heading structure type in section 14.8.4.3.2.

Test results:

• Test id 5 (PDF with correctly tagged headings)

3.1.1 Language of Page: The default human language of each Web page can be programmatically determined. (Level A)

PDF provides support for language identification for documents. The ISO 32000-1 PDF Specification details language support in section 14.9.2.

Test results:

• Test id 16 (document with non-English default language)

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)

PDF provides support for language identification for parts of documents.

Test results:

Test id 17 (Document with English primary language which includes Spanish phrases)

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)

No Accessibility Support impact.

PDF document authors can provide a link to a definition of unusual words or phrases.

3.1.4 Abbreviations: A mechanism for identifying the expanded form or meaning of abbreviations is available. (Level AAA)

PDF document authors can provide an explanation for abbreviations either by providing the expanded form immediately following the first instance of the abbreviation, by linking to a definition of the abbreviation, or by providing expansion text as a text equivalent to the abbreviation text.

PDF supports abbreviations in tagged PDF by using a span and an abbreviation property. The ISO 32000-1 PDF Specification details abbreviation support in section 14.9.5.

Test results:

• Test id 18 (Markup abbreviations in PDF tags)

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)

No Accessibility Support impact.

This is design-specific.  Application or document authors need to consider this provision and ensure conformance.

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)

PDF documents support this success criteria when document authors provide pronunciation information using general techniques:

• G120: Providing the pronunciation immediately following the word
• G121: Linking to pronunciations
• G62: Providing a glossary

3.2.1 On Focus: When any component receives focus, it does not initiate a change of context. (Level A)

Standard controls in PDF do not initiate changes of context when receiving focus. The ISO 32000-1 PDF Specification details control types in section 12.7.4.

Test results:

• Test id 19 (Standard Button control)
• Test id 20 (Standard CheckBox control)
• Test id 21 (Standard ComboBox control)
• Test id 22 (Standard ListBox control)
• Test id 23 (Standard Radio Button control)
• Test id 24 (Standard Text Field control)

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)

Standard controls in PDF do not initiate changes of context when changing settings. The ISO 32000-1 PDF Specification details control types in section 12.7.4.

Test results:

• Test id 25 (Button)
• Test id 26 (CheckBox)
• Test id 27 (ComboBox)
• Test id 28 (ListBox)
• Test id 29 (Radio Button)
• Test id 30 (Text Field)

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)

No Accessibility Support impact.

This is design-specific.  Application or document authors need to consider this provision and ensure conformance.

3.2.4 Consistent Identification: Components that have the same functionality within a set of Web pages are identified consistently. (Level AA)

No Accessibiltiy Support impact.

This is design-specific.  Application or document authors need to consider this provision and ensure conformance.

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)

Changes of context are not initiated by default for any user interface controls.

Test results:

• See test ids 19-30

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)

PDF form controls that accept user input provide validation functionality which can alert the user of the error in text.

Test results:

• Test id 31 (Error Validation)

3.3.2 Labels or Instructions: Labels or instructions are provided when content requires user input. (Level A)

PDF form controls allow authors to provide labels or instructions.

Test results:

• Test id 32 (Sample form with correctly labeled controls)

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)

PDF form controls that accept user input provide validation functionality which can alert the user of the error in text.  PDF supports scripting functionality which allows customization of error responses, enabling the provision of suggestions when possible.

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, at least one of the following is true: (Level AA)

• Reversible: Submissions are reversible.
• Checked: Data entered by the user is checked for input errors and the user is provided an opportunity to correct them.
• Confirmed: A mechanism is available for reviewing, confirming, and correcting information before finalizing the submission.

No Accessibility Support impact. 

This is design-specific. Application or document authors need to consider this provision and ensure conformance. In such forms, PDF authors are able to utilize validation or server-side error-checking prior to final submission.

3.3.5 Help: Context-sensitive help is available. (Level AAA)

PDF authors can provide context-sensitive help by utilizing the following general techniques:

• G71: Providing a help link on every Web page
• G184: Providing text instructions at the beginning of a form or set of fields that describes the necessary input

3.3.6 Error Prevention (All): For Web pages that require the user to submit information, at least one of the following is true: (Level AAA)

• Reversible: Submissions are reversible.
• Checked: Data entered by the user is checked for input errors and the user is provided an opportunity to correct them.
• Confirmed: A mechanism is available for reviewing, confirming, and correcting information before finalizing the submission.

No Accessibility Support impact. 

This is design-specific. Application or document authors need to consider this provision and ensure conformance. In such forms, PDF authors are able to utilize validation or server-side error-checking prior to final submission.

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)

Note: Start and end tags that are missing a critical character in their formation, such as a closing angle bracket or a mismatched attribute value quotation mark are not complete.

PDF documents are not implemented using markup languages.  An equivalent process for ensuring that PDF documents conform to the PDF specification or variation thereof can be tested in Adobe Acrobat.

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)

Note: This success criterion is primarily for Web authors who develop or script their own user interface components. For example, standard HTML controls already meet this success criterion when used according to specification.

Standard controls in PDF provide name, role, and value when used according to specification. The ISO 32000-1 PDF Specification details structure types in section 14.8.4.

Test results:

• Test id 33 (Button)
• Test id 34 (CheckBox)
• Test id 35 (ComboBox)
• Test id 36 (ListBox)
• Test id 37 (Radio Button)
• Test id 38 (Text Field)
• Test id 39 (Links)
• Test id 40 (Comments)
• Test id 41 (Tables)
• Test id 42 (Nested Lists)
• Test id 43 (Headings)