Let’s say you’re so impressed with this article series on WCAG that you’re searching your local library for a book to send the author as a homage to their overwhelming talent.
You’re looking for a particular title, but you aren’t sure of the book’s author, so you spend some time trying different keywords in the search bar and playing around with different filters.
However, as you navigate between the main search window and different catalog entries, you notice that the search bar and filter list change their locations on the page. You might find this mildly annoying, but for some users, it could inhibit their ability to use the site.
Any navigational mechanisms on your site should retain their same relative location and order if they are repeated on multiple pages. This will prove helpful to users experiencing low or no vision, cognitive limitations, or intellectual disabilities, who rely on navigational elements being in predictable places.
People with low vision, for instance, often utilize screen magnifiers to display a small portion of a page at a time and depend on visual cues and page boundaries to find repeated content, like navigation menus.
Even with this rule in practice, users may still initiate such a change through system preferences or adaptive user agents. WCAG only stresses that you, as a content author, avoid changing the relative order of navigation elements between your site’s pages.