# Aside should not be contained in another landmark

> Canonical HTML version: https://rocketvalidator.com/accessibility-validation/axe/4.9/landmark-complementary-is-top-level
> Attribution: Rocket Validator (https://rocketvalidator.com)
> License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/)

Ensures the complementary landmark or aside is at top level.

Complementary content is content that supports the primary idea of a page or document. Users of screen readers have the option to bypass supplemental content that shows at the accessibility API's top level. Embedding an `<aside>` element within another landmark may prevent the ability for screen reader users to browse through supplemental content.

<h3>What this Accessibility Rule Checks</h3>

Do not insert `<aside>` elements or elements containing `role="complementary"` inside landmark-marked content.