html-aria Utilities for creating accessible HTML based on the latest ARIA 1.3 specs and latest HTML in ARIA recommendations. Lightweight, performant, tree-shakeable, and 0 dependencies.
This is designed to be a better replacement for aria-query when working with HTML. The reasons are:
- html-aria is designed to reduce mistakes, while aria-query’s APIs are easy to “hold it wrong.” The information may not be _incorrect_, but often are locked behind several successful operations you must know to connect to get the right result.ARIA 1.3 spec , but that’s only one part. There are also the HTML Accessibility API Mappings and HTML to ARIA specs that are critical to working with HTML. While aria-query follows these other documents when it can, its design makes it difficult to apply the advice from all specs, often producing incomplete or incorrect results.
html-aria is also ESM-compatible and more performant .
Usage
$3 ``sh`
$3 This library works both in Node.js and the browser. But works best when the DOM is accessible , either the actual DOM or a virtualized one like JSDOM. The reason is the spec requires DOM traversal—identifying an element’s context in parents and children, as well as attributes of the element. In a DOM environment, html-aria will do all the work for you; in Node.js you must provide complete information about attributes, and sometimes ancestors.
$3 Though this library is NOT a lint plugin, it can do most of the work for you. You only need to traverse the AST of the language you’re using (e.g. HTML vs React vs Svelte), and html-aria can validate the nodes.
#### Node.js (ESLint + React plugin)
`ts
const createRule = ESLintUtils.RuleCreator(
export default createRule({
const tagName = node.name.name as TagName;
// 1. assemble attributes into a map
// 2. get supported attributes from html-aria (which MUST include the attributes to work properly)
// 3. validate
_Have an improvement to suggest? Please open a PR!_
API
$3 Determine which HTML maps to which default ARIA role.
`ts
// DOM
// Node.js (no DOM)
It’s important to note that inferring ARIA roles from HTML isn’t always straightforward! There are 3 types of role inference:
1. Tag map : 1 tag → 1 ARIA role.Tag + attribute map : Tags + attributes are needed to determine the ARIA role (e.g. input[type="radio"] → radio)Tag + DOM tree : Tags + DOM tree structure are needed to determine the ARIA role.
See a list of all elements .
$3 The spec dictates that certain elements may NOT receive certain roles. For example,
is allowed (not recommended, but allowed), but is not. getSupportedRoles() will return all valid roles for a given element + attributes.
`ts// DOM
// Node.js (no DOM)
`There is also a helper method
to make individual assertions:
`tsisSupportedRole({ tagName: "select" }, "combobox"); // true
`
$3 For any element, list all supported aria-\* attributes , including attributes inherited from superclasses. This takes in an HTML element, not an ARIA role, because in some cases the HTML element actually affects the list (see full list ).
tsgetSupportedAttributes({ tagName: "button" }); // ["aria-atomic", "aria-braillelabel", …]
`If you want to look up by ARIA role instead, just pass in a placeholder element:
ts`There’s also a helper method
to test individual attributes:
`tsisSupportedAttribute({ tagName: "button" }, "aria-pressed"); // true
`It’s worth noting that HTML elements may factor in according to the spec—providing the
isn’t enough. See aria-\* attributes from HTML .
$3 Return all HTML elements that represent a given ARIA role, if any. If no HTML elements represent this role,
undefined will be returned. This is essentially the inverse of getRole().
`tsgetElements("button"); // [{ tagName: "button" }]
`Worth noting that this is slightly-different from a related concept or base concept .
$3 Return
if a given HTML tag _MAY_ be interacted with or not. It does NOT check if an element is interactive in the moment (e.g. it won’t account for display: none or more advanced scenarios).
`ts`The methodology for this follows the complete ARIA specification:
1. If the role is a widget or window subclass, then it is interactive
, and if it natively is NOT a widget or window role, tabindex must also be supplieddisabled or aria-disabled, then it is NOT interactiveseparator Note that
aria-hidden elements MAY be interactive (even if it’s not best practice) as a part of 2.4.5 Multiple Ways if an alternative is made for screenreaders, etc.
$3 For a role, return whether or not an accessible name is required for screenreaders.
`tsisNameRequired("link"); // true
`_Note: this does NOT mean
is required! Quite the opposite—if a name is required, it’s always best to have the name visible in content. See ARIA 1.3 Accessible Name Calculation for more info._
$3 Some aria-\ attributes require specific values.
isValidAttributeValue() returns false if, given a specific aria-\ attribute, the value is invalid according to the spec.
`ts// string attributes
true except for an empty string// boolean attributes
// enum attributes
// number attributes
`⚠️ _Be mindful of cases where a valid value may still be valid, but invoke different behavior according to the ARIA role, e.g.
behavior for radio/menuitemradio/switch_
$3 Get the accessible name and description for an HTML element.
`ts`> [!NOTE]
. But simple calculations like aria-label are well-supported.
Reference
$3 This outlines the requirements to adhere to the W3C spec when it comes to inferring the correct ARIA roles from HTML. Essentially, there are 3 types of inference:
1. Tag map : 1 tag → 1 ARIA role.Tag + attribute map : Tags + attributes are needed to determine the ARIA role (e.g.
input[type="radio"] → radio)Tag + DOM tree : Tags + DOM tree structure are needed to determine the ARIA role.Here are all the HTML elements where either attributes, hierarchy, or both are necessary to determine the correct role. Any HTML elements not listed here follow the simple “tag map” approach (keep in mind that aria-\* attributes may not follow the same rules !).
| Element | Role | Attribute-based | Hierarchy-based |a |
generic \| link | ✅ | |area | generic \| link | ✅ | |footer | contentinfo \| generic | | ✅ |header | banner \| generic | | ✅ |input | button \| checkbox \| combobox \| radio \| searchbox \| slider \| spinbutton \| textbox | ✅ | |li | listitem \| generic | | ✅ |section | generic \| region | ✅ | |select | combobox \| listbox | ✅ | |td | cell\| gridcell \| — | | ✅ |th | columnheader \| rowheader \| — | ✅ | ✅ |_Note:
— = no corresponding role _
$3 Further, a common mistake many simple accessibility libraries make is mapping aria-\* attributes to ARIA roles. While that _mostly_ works, there are a few exceptions where HTML information is needed. That is why
getSupportedAttributes() takes an HTML element. Here is a full list:| Element | Default Role | Notes |audio | — | Accepts
application aria-\* attributes by default |base | generic | No aria-\* attributes allowed |body | generic | Does NOT allow aria-hidden="true" |br | generic | No aria-\* attributes allowed EXCEPT aria-hidden |col | — | No aria-\* attributes allowed |colgroup | — | No aria-\* attributes allowed |datalist | listbox | No aria-\* attributes allowed |head | — | No aria-\* attributes allowed |html | — | No aria-\* attributes allowed |img (no alt) | none | No aria-\* attributes allowed EXCEPT aria-hidden |input[type=checkbox] | — | Forbids aria-checked |input[type=color] | — | Acts as a generic element but allows aria-disabled |input[type=files] | — | Acts as a generic element but allows aria-disabled, aria-invalid, and aria-required |input[type=hidden] | — | No aria-\* attributes allowed |input[type=radio] | — | Forbids aria-checked |link | — | No aria-\* attributes allowed |map | — | No aria-\* attributes allowed |meta | — | No aria-\* attributes allowed |noscript | — | No aria-\* attributes allowed |picture | — | No aria-\* attributes allowed EXCEPT aria-hidden |script | — | No aria-\* attributes allowed |slot | — | No aria-\* attributes allowed |source | — | No aria-\* attributes allowed |style | — | No aria-\* attributes allowed |summary | — | Allows aria-disabled and aria-haspopup regardless of role |template | — | No aria-\* attributes allowed |title | — | No aria-\* attributes allowed |track | — | No aria-\* attributes allowed EXCEPT aria-hidden |video | — | Accepts application aria-\* attributes by default |wbr | — | No aria-\* attributes allowed EXCEPT aria-hidden |_Note:
— = no corresponding role . Also worth pointing out that in other cases, global aria-\* attributes are allowed, so this is unique to the element and NOT the ARIA role._
$3 Though the HTML in ARIA spec was the foundation for this library, at points it conflicts with AAM . We also have browsers sometimes showing inconsistent roles, too. For these discrepancies, we compare what the specs recommend, along with the library’s current decision in an attempt to follow the most helpful path.
| Element | HTML in ARIA | AAM | Browsers\* | html-aria |
| No corresponding role | definition | definition | definition | | No corresponding role | list | (inconsistent) | No corresponding role | | No corresponding role | term | term | term | | No corresponding role | caption | caption (Figcaption in Chrome) | caption | | No corresponding role | mark | mark | mark | | graphics-document | graphics-document | graphics-document (Firefox), img (Chrome), generic (Safari) | graphics-document |_\* Chrome 132, Safari 18, Firefox 135._
$3 #### Node.js ignores necessary ancestor-based roles
There are 2 categories of context-dependent element usage: necessary and conditional .
“Necessary“ context elements require certain parents to use correctly, like table-based elements (
, , , etc.) requiring table parents (, , etc.) and list-based elements requiring list parents (, , etc.). Without their parents, they have no purpose and their behavior is unpredictable, with some browsers even stripping elements out of the DOM. These elements will 99% of the time be used in their intended contexts.The DOM environment follows the ARIA spec. But in a Node.js context, it’s likely we are statically analyzing a component where the parents aren’t immediatly reachable—they may be in another file. If we assume the elements are used correctly even when we can’t see the ancestors, we can show more accurate errors and warnings, rather than requiring the consumer to do work that is technically and computationally difficult.
So for the reasons above, assuming the elements are used out of context is more likely to result in less predictable behavior that could lead to mistakes. To treat elements as if they _are_ used out of their context in Node.js, pass an empty
ancestors array as an explicit way to declare it.
`tsgetRole({ tagName: "td" }, { ancestors: [] }); // undefined
`These are all the elements that have assumed context (i.e. different behavior in Node.js):
, , , , , , , , , , .“Conditional” context elements may either have certain parents or not, all of which are valid.
used in the body is a landmark complementary role; inside a it’s generic (unless it has an accessible name, then it’s complementary again). is a banner landmark itself, or inside another landmark is generic. Since there’s no “wrong” usage here, In Node.js they behave as expected, so they don’t deviate from DOM behavior or the spec.
`tsgetRole({ tagName: "header" }); // "banner"
`
$3 #### Why the
object syntax?Most of the time this library will be used in a Node.js environment, likely outside the DOM (e.g. an ESLint plugin traversing an AST). While most methods also allow an HTMLElement as input, the object syntax is universal and works in any context.
#### What’s the difference between “no corresponding role” and the
none role?From the spec :
No corresponding role
> The elements marked with _No corresponding role _, in the second column of the table do not have any implicit ARIA semantics , but they do have meaning and this meaning may be represented in roles, states and properties not provided by ARIA, and exposed to users of assistive technology via accessibility APIs. It is therefore recommended that authors add a
role attribute to a semantically neutral element such as a div or span , rather than overriding the semantics of the listed elements.
none role> An element whose implicit native role semantics will not be mapped to the accessibility API . See synonym presentation .
In other words,
none is more of a decisive “this element is presentational and can be ignored” labeling, while “no corresponding role” means “this element doesn’t have predefined behavior that can be automatically determined, and the author should provide additional information such as explicit roles and ARIA states and properties.”In html-aria, “no corresponding role” is represented as
undefined`.#### What is the difference between “unsupported attributes” and “prohibited attributes?”
In the spec, you’ll find language describing both roles and attributes in 4 categories:
1. Supported and recommended: valid and recommended to useSupported but not recommended: valid, but may cause unpredictable behavior Unsupported, but not prohibited: these are omitted both from supported and prohibited listsUnsupported and prohibited: explicitly prohibited
As stated in Project Goals , html-aria aims to not conflate non-normative recommendations as normative guidelines. So in the API, getSupportedRoles() and getSupportedAttributes() will return 1 and 2, but not 3 or 4.
While there is a technical distinction between 3 and 4, for the purposees of html-aria they’re treated the same (because 3 specifically is not explicitly allowed, we can make a choice to read it as prohibited).
About
$3 1. Implement _all_ ARIA spec docs, not just the roles specification