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.
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.
noPositiveTabindex	Prevent the usage of positive integers on tabindex attribute.
noRedundantAlt	Enforce img alt prop does not contain the word “image”, “picture”, or “photo”.
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.
useAriaPropsForRole	Enforce that elements with ARIA roles must have all required ARIA attributes for that role.
useButtonType	Enforces the usage and validity of the attribute type for the element button
useHtmlLang	Enforce that html element has lang attribute.
useIframeTitle	Enforces the usage of the attribute title for the element iframe.
useMediaCaption	Enforces that audio and video elements must have a track for captions.
useValidAriaRole	Elements with ARIA roles must use a valid, non-abstract ARIA role.
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.
noScriptUrl	Disallow javascript: URLs in HTML.
noSyncScripts	Prevent the usage of synchronous scripts.
noVueVIfWithVFor	Disallow using v-if and v-for directives on the same element.
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 arguments 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)
• noAutofocus (Severity: error)
• noDistractingElements (Severity: error)
• noHeaderScope (Severity: error)
• noPositiveTabindex (Severity: error)
• noRedundantAlt (Severity: error)
• noSvgWithoutTitle (Severity: error)
• useAltText (Severity: error)
• useAnchorContent (Severity: error)
• useAriaPropsForRole (Severity: error)
• useButtonType (Severity: error)
• useHtmlLang (Severity: error)
• useIframeTitle (Severity: error)
• useMediaCaption (Severity: error)
• useValidAriaRole (Severity: error)
• useValidLang (Severity: error)

Missing a rule? Help us by contributing to the analyzer or create a rule suggestion here.