HTML Checking for Large Sites

A <div> element is using ARIA attributes, but its role has not been defined. ARIA defines semantics that can be applied to elements, with these divided into roles (defining a type of user interface element) and states and properties that are supported by a role. Authors must assign an ARIA role and the appropriate states and properties to an element during its life-cycle, unless the element already has appropriate ARIA semantics (via use of an appropriate HTML element). Examples:

<!-- This div uses ARIA but its role is not clear, so it's invalid. -->
<div aria-expanded="true">...</div>

<!-- This div defines clearly its role, so it's valid. -->
<div role="navigation" aria-expanded="true">...</div>

<!-- Nav elements have an implicit navigation role so we don't need the role attribute. -->
<nav aria-expanded="true">...</nav>

Read about Using ARIA: Roles, states and properties.

A <div> tag has been found as a direct child of an <ul> tag, and this is not allowed. For example, <ul><div><li>item</li></div></ul> is not valid, but <ul><li><div>item</div></li></ul> is valid as the direct child of <ul> is <li>.