Glossary · Accessibility term
Bypass blocks
Bypass blocks is rule 2.4.1, and it asks for one thing at Level A. Somewhere there has to be a mechanism that gets a person past content repeated across pages, which in practice means the navigation. A skip link is the answer everybody reaches for and it is one of eight, because W3C offers two routes with several techniques under each. You can link past the block, or you can group the block so it can be skipped, and landmark regions or a real heading structure do the second on their own. It is narrower than it sounds, too. Individual words, phrases and single links are not blocks. And browsers already provide a keyboard route back to the top of a page, so where the navigation sits in the footer W3C says a skip link there may be unnecessary.
In practice
The usual implementation is a skip link, hidden until it takes focus, sitting as the first tab stop and jumping to the main content. Two other links are worth knowing about. One at the start of a repeated block that jumps to the end of that block, which suits something long sitting in the middle of a page. And a set of links at the top pointing at each area of content, which is closer to a table of contents and is the answer for a mega-menu. A menu that genuinely collapses counts as well, so a site can pass with no skip link anywhere.
The grouping routes pass on paper and often fail on the page, because both need somewhere to land. In the 2026 WebAIM Million, 84.3% of home pages carried at least one landmark and only 46.1% carried a main landmark to skip to. Heading structure fares no better, with 41.8% of pages skipping levels. A skip link pointing at nothing and a landmark structure with no main are the same failure in different clothes.
The scope has edges people argue about and W3C has already settled them. The rule reaches content repeated across a set of pages that share a purpose and an author. So a checkout that strips the site navigation is answering to its own set, and W3C uses that exact example. What it does not do is leave the checkout free. If those pages repeat a block of their own, that block is what the rule now asks about. Content repeated inside a single page is helpful to skip and not required at all. And advertising frames are on W3C's own list of repeated blocks, which surprises most ad-funded sites.
Why it matters
Without it, somebody moving through the page one stop at a time meets your entire menu before the content, on every page they open. That is keyboard users and screen reader users both, because sequential navigation is what they have in common, while a sighted mouse user simply looks at the middle of the screen and clicks. On a site with thirty navigation items that is thirty presses per page view, before anybody has read a word of what they came for. Nobody budgets for that.
Two routes, not one
A skip link that jumps to main satisfies the rule. So does a page whose navigation, main content and footer are real landmarks a screen reader can move between, with nothing added at all. The catch is that the landmark route only works if there is a main landmark to arrive at, and fewer than half of home pages have one.
Where this shows up on the site
Related terms
- Skip linkA skip link is usually the first link on a page, often reading "Skip to main content", and hidden until it takes focus.
- LandmarkA landmark is a named region of a page that assistive technology can list and jump straight to, and there are eight of them.
- Keyboard accessibilityKeyboard accessibility means every piece of functionality on the page can be operated through a keyboard interface.
- Heading structureHeading structure is the h1 to h6 outline of a page, and for screen reader users it is the map.
- Focus orderFocus order is the sequence focus travels in as you press Tab, and by default it follows the order elements appear in the code rather than the order they appear on screen.
Knowing the word is the easy part.
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