HTML Checking for Large Sites

The <h1> through <h6> elements are headings for the sections with which they are associated. They should not be empty, for example <h1></h1> is invalid.

A heading element (h1, h2, h3, etc.) can’t be nested inside another heading element.

Here’s an example of invalid HTML code:

<h1>Main heading
  <h2>Sub heading</h2>
</h1>

To fix this issue, you should ensure that each heading element is properly nested within the document hierarchy. Headings should only be used to indicate the structure of your content, not to style it.

Here’s an example of valid HTML code that properly uses heading elements:

<main>
  <h1>Main heading</h1>
  <section>
    <h2>Section heading</h2>
    <p>Paragraph content</p>
  </section>
</main>

In this example, the heading elements are used to denote the structure of the document, with the h1 element indicating the highest level heading and the h2 element indicating a subheading within a section. Notice that in the valid example, each heading element is only used once and is not nested within another heading element.

Some times this can be caused by a typo in the end tag for a heading, for example:

<h3>Meet the Feebles<h3>

In order to fix this issue, the end tag should be </h3> in the example above.

The heading role defines this element as a heading to a page or section, and is implicit in tags <h1> to <h6>.

The heading role indicates to assistive technologies that this element should be treated like a heading. Screen readers would read the text and indicate that it is formatted like a heading.

This ARIA role is only needed to add that role to a generic element like <div>, for example:

<div role="heading" aria-level="1">This is a main page heading</div>

This defines the text in the <div> to be the main heading of the page, indicated by being level 1 via the aria-level attribute. Opt for using the <h1> (thru <h6>) element instead:

<h1>This is a main page heading</h1>