HTML Rules

Below the list of rules supported by Biome, divided by group. Here’s a legend of the emojis:

• The icon indicates that the rule is part of the recommended rules.
• The icon indicates that the rule provides a code action (fix) that is safe to apply.
• The icon indicates that the rule provides a code action (fix) that is unsafe to apply.
• The icon indicates that the rule has been implemented and scheduled for the next release.

a11y

Rule name	Description	Properties
noAccessKey	Enforce that the accesskey attribute is not used on any HTML element.
noAriaHiddenOnFocusable	Enforce that aria-hidden=“true” is not set on focusable elements.
noAriaUnsupportedElements	Enforce that elements that do not support ARIA roles, states, and properties do not have those attributes.
noAutofocus	Enforce that the autofocus attribute is not used on elements.
noDistractingElements	Enforces that no distracting elements are used.
noHeaderScope	The scope prop should be used only on <th> elements.
noInteractiveElementToNoninteractiveRole	Enforce that non-interactive ARIA roles are not assigned to interactive HTML elements.
noLabelWithoutControl	Enforce that a label element or component has a text label and an associated input.
noNoninteractiveElementInteractions	Disallow use event handlers on non-interactive elements.
noNoninteractiveElementToInteractiveRole	Enforce that interactive ARIA roles are not assigned to non-interactive HTML elements.
noNoninteractiveTabindex	Enforce that tabindex is not assigned to non-interactive HTML elements.
noPositiveTabindex	Prevent the usage of positive integers on tabindex attribute.
noRedundantAlt	Enforce img alt prop does not contain the word “image”, “picture”, or “photo”.
noRedundantRoles	Enforce explicit role property is not the same as implicit/default role property on an element.
noStaticElementInteractions	Enforce that static, visible elements (such as <div>) that have click handlers use the valid role attribute.
noSvgWithoutTitle	Enforces the usage of the title element for the svg element.
useAltText	Enforce that all elements that require alternative text have meaningful information to relay back to the end user.
useAnchorContent	Enforce that anchors have content and that the content is accessible to screen readers.
useAriaActivedescendantWithTabindex	Enforce that tabindex is assigned to non-interactive HTML elements with aria-activedescendant.
useAriaPropsForRole	Enforce that elements with ARIA roles must have all required ARIA attributes for that role.
useAriaPropsSupportedByRole	Enforce that ARIA properties are valid for the roles that are supported by the element.
useButtonType	Enforces the usage and validity of the attribute type for the element button
useFocusableInteractive	Elements with an interactive role and interaction handlers must be focusable.
useHeadingContent	Enforce that heading elements (h1, h2, etc.) have content and that the content is
useHtmlLang	Enforce that html element has lang attribute.
useIframeTitle	Enforces the usage of the attribute title for the element iframe.
useKeyWithClickEvents	Enforce elements with a click event handler to also have at least one keyboard event handler.
useKeyWithMouseEvents	Enforce that onmouseover is accompanied by onfocus and onmouseout by onblur.
useMediaCaption	Enforces that audio and video elements must have a track for captions.
useSemanticElements	Enforces using semantic DOM elements over the ARIA role property.
useValidAnchor	Enforce that all anchors are valid, and they are navigable elements.
useValidAriaProps	Ensures that ARIA properties aria-* are all valid.
useValidAriaRole	Elements with ARIA roles must use a valid, non-abstract ARIA role.
useValidAriaValues	Enforce that ARIA state and property values are valid.
useValidAutocomplete	Use valid values for the autocomplete attribute on input elements.
useValidLang	Ensure that the attribute passed to the lang attribute is a correct ISO language and/or country.

nursery

Rule name	Description	Properties
noAmbiguousAnchorText	Disallow ambiguous anchor descriptions.
noDuplicateAttributes	Disallow duplication of attributes.
noExcessiveLinesPerFile	Restrict the number of lines in a file.
noInlineStyles	Disallow the use of inline styles.
noScriptUrl	Disallow javascript: URLs in HTML.
noSyncScripts	Prevent the usage of synchronous scripts.
noUndeclaredClasses	Reports CSS class names in HTML class attributes that are not defined
noVueVIfWithVFor	Disallow using v-if and v-for directives on the same element.
useIframeSandbox	Enforce the ‘sandbox’ attribute for ‘iframe’ elements.
useScopedStyles	Enforce that <style> blocks in Vue SFCs have the scoped attribute and that <style> blocks in Astro components do not have the is:global directive.
useVueConsistentVBindStyle	Enforce a consistent style for v-bind in Vue templates.
useVueConsistentVOnStyle	Enforce a consistent style for v-on in Vue templates.
useVueHyphenatedAttributes	Enforce hyphenated (kebab-case) attribute names in Vue templates.
useVueVForKey	Enforce that elements using v-for also specify a unique key.
useVueValidTemplateRoot	Enforce valid Vue <template> root usage.
useVueValidVBind	Forbids v-bind directives with missing values or invalid modifiers.
useVueValidVCloak	Enforce valid v-cloak Vue directives.
useVueValidVElse	Enforce valid usage of v-else.
useVueValidVElseIf	Enforce valid v-else-if directives.
useVueValidVHtml	Enforce valid v-html directives.
useVueValidVIf	Enforces valid v-if usage for Vue templates.
useVueValidVOn	Enforce valid v-on directives with proper arguments, modifiers, and handlers.
useVueValidVOnce	Enforce valid v-once Vue directives.
useVueValidVPre	Enforce valid v-pre Vue directives.
useVueValidVText	Enforce valid v-text Vue directives.
useVueVapor	Enforce opting in to Vue Vapor mode in <script setup> blocks.

Recommended rules

• noAccessKey (Severity: error)
• noAriaHiddenOnFocusable (Severity: error)
• noAriaUnsupportedElements (Severity: error)
• noAutofocus (Severity: error)
• noDistractingElements (Severity: error)
• noHeaderScope (Severity: error)
• noInteractiveElementToNoninteractiveRole (Severity: error)
• noLabelWithoutControl (Severity: error)
• noNoninteractiveElementToInteractiveRole (Severity: error)
• noNoninteractiveTabindex (Severity: error)
• noPositiveTabindex (Severity: error)
• noRedundantAlt (Severity: error)
• noRedundantRoles (Severity: error)
• noStaticElementInteractions (Severity: error)
• noSvgWithoutTitle (Severity: error)
• useAltText (Severity: error)
• useAnchorContent (Severity: error)
• useAriaActivedescendantWithTabindex (Severity: error)
• useAriaPropsForRole (Severity: error)
• useAriaPropsSupportedByRole (Severity: error)
• useButtonType (Severity: error)
• useFocusableInteractive (Severity: error)
• useHeadingContent (Severity: error)
• useHtmlLang (Severity: error)
• useIframeTitle (Severity: error)
• useKeyWithClickEvents (Severity: error)
• useKeyWithMouseEvents (Severity: error)
• useMediaCaption (Severity: error)
• useSemanticElements (Severity: error)
• useValidAnchor (Severity: error)
• useValidAriaProps (Severity: error)
• useValidAriaRole (Severity: error)
• useValidAriaValues (Severity: error)
• useValidAutocomplete (Severity: error)
• useValidLang (Severity: error)

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