|Version:||WCAG 2.0 and up|
When the sequence in which content is presented affects its meaning, a correct reading sequence can be programmatically determined.
The purpose of this success criterion is to ensure that users who cannot perceive the content can still follow the logical reading ordering of the publication (i.e., the visual sequencing of the content does not change the primary narrative).
How to Meet
This success criterion mostly commonly affects fixed-layout publications where authors can use CSS to position content in a different sequence visually. Dialogue, for example, can be misordered in the markup but made to read logically visually.
Therefore, to meet this success criterion, the order of content in the markup must match the expected reading order.
This success criterion applies across page boundaries, as the narrative continues from document to document. Sidebars, images, tables and other content split across documents has to make sense from page to page, not just within the document that contains it.
For example, consider a sidebar split across the bottom of two pages. If the markup for each part of the sidebar is the last item in each document, users will struggle to follow the text from document to document. In a case like this, the portion of the sidebar on the second page should be ordered first so that a reader who starts reading it on the first page can continue reading it to its conclusion immediately on the second. The author can then visually style the location to match with the preceding page's layout.
The following knowledge base pages provide more information about how to address this success criterion for publishing content: