`no-duplicate-h1`

Warn if there is more than one h1 element in the document.

Split out of the former required-h1 rule, alongside require-h1.

❌ Examples of incorrect code for this rule

<html>
  <body>
    <h1>heading</h1>
    <main>
      <h1>another heading</h1>
    </main>
  </body>
</html>

✅ Examples of correct code for this rule

<html>
  <body>
    <h1>heading</h1>
    <main>
      <h2>subheading</h2>
    </main>
  </body>
</html>

Interface

{
  "no-duplicate-h1": boolean
}

{
  "no-duplicate-h1": {
    "options": {
      "in-document-fragment"?: boolean
    }
  }
}

Property	Type	Default Value	Description
`in-document-fragment`	`boolean`	`"false"`	Set it to `true` if you want this rule to apply within document fragment rather than the entire document.

warning