Are ARIA landmarks that should only exist once limited to only existing once?

Certain ARIA landmarks – role=”banner”, role=”main”, and role=”contentinfo” – are only permitted to appear on the page once for ARIA validation to meet the standard. This also includes the HTML equivalents – <header>, <main>, and <footer>.

Why this matters

See Why does it matter if our HTML is semantic?

How to implement

Having a <main> and a <div role=”main”> on the same page at the same time is a failure of this requirement.

• Ensure that there is only one “header” container on the page, and that it is either <header> or role=”banner”.
• Ensure that there is only one “main” container on the page, and that it is either <main> or role=”main”.
• Ensure that there is only one “footer” container on the page, and that it is either <footer> or role=”contentinfo”.

How to test

Right-click and inspect the page, confirming that:

• There is only one “header” container on the page, and that it is either <header> or role=”banner”.
• There is only one “main” container on the page, and that it is either <main> or role=”main”.
• There is only one “footer” container on the page, and that it is either <footer> or role=”contentinfo”.