When the sequence in which content is presented affects its meaning, a correct reading sequence can be programmatically determined. (Level A)

Rationale

If the visual order of information on the page is important to its meaning, then the sequence of the information must be available programmatically.

Teams need to do two things to achieve the goal of this checkpoint:

  1. Determine if any information being presented has a meaningful order
  2. Ensure that the meaningful order is available to assistive technologies

An example of meaningful sequence is text in a two-column article. A user must read the lines of text in the first column sequentially, then move to the second column and do the same. If an assistive technology reads across both columns (e.g., reads the first line of the first column then the first line of the second column) before proceeding to the next line, the user will obviously not understand the meaning. Other potential failures of meaningful sequence can occur when using CSS, layout tables or white space to position content.

It is important not to confuse the reading order with the navigation order. The ability to navigate (i.e., move by keyboard between interactive controls) in a way that preserves meaning is covered by the Focus Order checkpoint. Meaningful Sequence is concerned solely with the reading order, and so cannot normally be tested without assistive technology, which accesses content in a serialized manner by using programmatic methods.

Note: Sequence is not important for some content. For example, it does not normally affect meaning whether side navigation is read before or after the main content. So while matching the visual and reading order is a way to ensure this checkpoint is met, a difference in visual order and reading order is not a failure where the sequence does not affect the meaning.

Refer to Understanding SC 1.3.2 for more information (external link to WCAG).

Development Techniques

Review the General techniques as well as other tabs applicable to your technology.  Prioritize the use of technology-specific techniques, and implement the General techniques as needed. You are always required to find, understand and implement accessible code techniques to meet the checkpoint. The documented techniques and supplements are not exhaustive; they illustrate acceptable ways to achieve the spirit of the checkpoint. If numbered, techniques are in order of preference, with recommended techniques listed first. Where used, IBM information that complements the WCAG techniques is indicated as supplemental.

General techniques

Any item in this section represents a technique deemed sufficient. Ensure you review WCAG Common Failures to avoid development mistakes.

Mobile (iOS) techniques

The accessibilityElements protocol returns the list of accessible elements. Returning the elements in a logical order changes the navigation sequence.
It is also important to arrange the view hierarchy in a logical order.

Content order example from the BBC Mobile Accessibility Guidelines site.

Eclipse techniques

Instructions: In addition to the General techniques, the Eclipse techniques in this section are deemed sufficient for meeting this checkpoint (1.3.2).

Programmatically expose bidirectional support

Programmatically set the Base Text Direction when the application supports bidirectional text. Refer to Eclipse Help, Supporting bidirectional text for full details.

For information on providing bidirectional support for structured text, visit Structured Text Overview.

Note: Links to Eclipse Help are based on the latest version of Eclipse at the time of this writing, Eclipse Mars 4.5.

Programmatically expose relations between objects and those containing them

Applications must programmatically expose relationships between objects and their parent objects containing them as outlined in Checkpoint 502.3.7 Hierarchical Relationships.

Windows-based (MSAA+IA2) techniques

Instructions: In addition to the General techniques, the Windows-based (MSAA+IA2) techniques in this section are deemed sufficient for meeting this checkpoint (1.3.2).

Programmatically expose the bidi options for controls supporting bidirectional text

Programmatically set the bidirectional options of text edit controls when the application supports bidirectional text. Refer to: Rich Edit control MSDN API reference for definitions of the messages EM_GETBIDIOPTIONS, EM_SETBIDIOPTIONS, EM_SETEDITSTYLE and EM_SETEDITSTYLE which define the options for bidirectional processing in rich edit controls.

Programmatically expose relations between objects and those containing them

Applications must programmatically expose relationships between objects and their parent objects containing them as outlined in Checkpoint 502.3.7 Hierarchical Relationships.


Most links in this checklist reside outside ibm.com at the Web Content Accessibility Guidelines (WCAG) 2.0. W3C Recommendation 11 December 2008: http://www.w3.org/TR/WCAG20/

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