2.4.1 Bypass Blocks (A)

The intent of this Success Criterion is to allow people who navigate sequentially through content more direct access to the primary content of the Web page. Web pages and applications often have content that appears on other pages or screens. Examples of repeated blocks of content include but are not limited to navigation links, heading graphics, and advertising frames. Small repeated sections such as individual words, phrases or single links are not considered blocks for the purposes of this provision.

Keyboard users (including users of assistive technology such as screen readers) generally navigate pages sequentially.

This is in contrast to a sighted user's ability to ignore the repeated material either by focusing on the center of the screen (where main content usually appears) or a mouse user's ability to select a link with a single mouse click rather than encountering every link or form control that comes before the item they want.

While assistive technologies usually provide functionality that allow users to navigate content based on structures such as headings (i.e. to get an overview of the document's heading structure, jump directly to the a particular heading, go to the previous/next heading, etc.), lists (for instance to jump over an entire list), or HTML5 section elements (for instance, to get an overview and jump directly to any <header>, <nav>, <main> or <footer>), keyboard users without any assistive technologies are limited in how they can navigate. In general, these users will simply be able to use TAB / SHIFT+TAB to move focus between focusable elements on the page. There is, therefore, no quick method available to keyboard users to move directly to key sections of a page, such as the main content area, the navigation menu, or the footer – instead, users will have to tab through all links and other focusable elements in sequence.

For this reason, while generally good heading structure and use of HTML5 section elements (see also success criterion 1.3.1 Info and relationships (level A)) are all valid mechanisms to allow assistive technology users to bypass blocks of content (and their absence, while not a fail under this criterion, should at least be noted as a best practice recommendation), for the purpose of this success criterion testers generally need to make a (subjective) judgment call whether or not the site would benefit from having a "skip link" or similar mechanism which would allow keyboard users without assistive technology to more easily navigate to key parts (generally, the main content) of the page.

This subjective assessment should be informed by how extensive the repeated blocks of content are on pages. For instance, if a site did not feature any skip links, but its header/navigation section (or any other repeated block of content) only contained a handful of links, the criterion should be marked as not applicable. If the site did use appropriate heading structure and/or HTML5 section elements, it should be marked as pass. However, if the header/navigation contained dozens of focusable components, the absence of a skip link should be marked as a fail.

Note: in the (usually unlikely) event that a page does not contain blocks of content that are repeated across multiple Web pages (e.g. a standalone page/samples that does not feature the overall site's header/navigation), this criterion is marked as not applicable.

Note: though generally this test concentrates on classic web pages with a header/navigation/main content/footer structure, pages may contain various "blocks of content that are repeated on multiple web pages"; for all such blocks of content, carry out the same evaluation.