ARIA Validator
Fast, secure, client-side utility running entirely in your browser with zero server dependencies.
ARIA Validator
Verify WAI-ARIA roles, states, and properties against official W3C specifications to eliminate broken screen reader announcements.
ARIA Validator - WAI-ARIA 1.2 Syntax, States & Attributes Checker: Free ARIA Validator tool: validate WAI-ARIA roles, states, and attributes for valid syntax, allowed pairings, and adherence to the W3C First Rule of ARIA.
How to Use the ARIA Validator
Paste HTML or Component Markup
Insert any HTML component featuring ARIA roles, states, and properties, or test with the sample tablist or modal dialog.
Analyze WAI-ARIA 1.2 Syntax
The validator verifies all role definitions, flags misspelled aria-* attributes, and checks boolean and enumeration values.
Detect Redundant Native Roles
Identifies unnecessary roles on native HTML5 elements (such as button role="button" or nav role="navigation") that violate the First Rule of ARIA.
Verify ID Reference Linkages
Validates that ID values specified in aria-labelledby, aria-describedby, and aria-controls exist within the document.
Comprehensive Guide: ARIA Validator
Accessible Rich Internet Applications (WAI-ARIA) 1.2 is a W3C specification that provides semantic markup for dynamic web widgets and complex custom user interfaces. While semantic HTML5 provides native accessibility for buttons, inputs, links, and headings, complex interactive widgets—such as tabbed interfaces, modal dialogs, comboboxes, tree views, and accordions—require ARIA roles, states, and properties so screen readers can announce their interactive behavior.
The First Rule of ARIA use states: "If you can use a native HTML element or attribute with the semantics and behavior you require already built-in, instead of re-purposing an element and adding an ARIA role, state or property to make it accessible, then do so." Overusing or misusing ARIA is one of the leading causes of broken assistive experiences. Applying redundant roles like `<button role="button">` clutters the accessibility tree, while applying incorrect roles can strip native element behaviors.
Syntax errors in ARIA attributes cause silent accessibility failures. Unlike invalid JavaScript that throws visible console errors, invalid ARIA (such as typing `aria-labelled-by` instead of `aria-labelledby`, or passing `aria-expanded="yes"` instead of `aria-expanded="true"`) is silently ignored by browser accessibility APIs. As a result, screen reader users receive zero announcement when an accordion expands or when a dialog modal opens.
ARIA relationship attributes—such as `aria-labelledby`, `aria-describedby`, and `aria-controls`—require precise ID references. If an input references an ID that does not exist in the DOM, assistive technologies cannot resolve the accessible name. Validating your ARIA syntax before deploying to production ensures your custom components interact reliably with NVDA, VoiceOver, and JAWS.
Key Features & Capabilities
W3C WAI-ARIA 1.2 Specification
Validates roles, states, and properties against the authoritative W3C technical standard.
Misspelling & Typos Detection
Catches silent typos like aria-labelled-by or aria-hidden="yes" that break screen reader announcements.
First Rule of ARIA Enforcement
Flags redundant roles on native HTML5 tags to keep the browser accessibility tree clean and performant.
ID Reference Integrity Check
Confirms that IDs referenced in aria-labelledby and aria-describedby exist in your markup.
Immediate Remediation Guidance
Provides specific code examples showing exactly how to correct invalid attributes.
100% Client-Side Privacy
Validates code completely within your browser sandbox with zero network roundtrips.
Frequently Asked Questions
Browsers ignore invalid or misspelled ARIA attributes entirely. Unlike JavaScript, HTML does not throw exceptions for invalid attributes. The browser simply drops the attribute from the accessibility tree, leaving the user interface without the intended accessible name, role, or dynamic state announcement.
The First Rule of ARIA states that if a native HTML5 element can fulfill your functional requirement (e.g. using <button> instead of <div role="button">, or using instead of a custom accordion), you should always prefer native HTML. Native elements come with built-in keyboard accessibility and screen reader support without requiring custom ARIA.
In HTML markup, all attribute values are parsed as strings. W3C ARIA specification requires aria-expanded to have the exact literal string values "true" or "false". In JSX/React, writing aria-expanded={true} compiles to aria-expanded="true" in HTML.
aria-label takes a literal string as its value (e.g. aria-label="Close dialog"). aria-labelledby takes one or more element IDs and uses the text content of those elements as the accessible name (e.g. aria-labelledby="modal-title-id"). aria-labelledby is preferred when visible text already exists on the screen.
While the W3C spec allows fallback roles separated by spaces (e.g. role="switch checkbox"), modern browser support is universal for WAI-ARIA 1.2 roles, and using multiple roles can cause unexpected behavior in older screen readers. The best practice is to specify a single, accurate role.