This specification describes the additions to the ARIA 1.2 specification which will make it possible for web authors to programmatically express Element semantics via an IDL interface.

IDL Interfaces

This section is part of the ARIA 1.2 Specification, and is included here for informative purposes only.

Conforming user agents MUST implement the following IDL interfaces.

Interface Mixin AccessibilityRole

interface mixin AccessibilityRole {
attribute DOMString? role;
Element implements AccessibilityRole;

ARIA Role Reflection

User agents MUST reflect the role content attribute as the role IDL attribute on Element instances.

Interface Mixin AriaAttributes

  interface mixin AriaAttributes {
    attribute DOMString? ariaActiveDescendant;
    attribute DOMString? ariaAtomic;
    attribute DOMString? ariaAutoComplete;
    attribute DOMString? ariaBusy;
    attribute DOMString? ariaChecked;
    attribute DOMString? ariaColCount;
    attribute DOMString? ariaColIndex;
    attribute DOMString? ariaColSpan;
    attribute DOMString? ariaControls;
    attribute DOMString? ariaCurrent;
    attribute DOMString? ariaDescribedBy;
    attribute DOMString? ariaDetails;
    attribute DOMString? ariaDisabled;
    attribute DOMString? ariaErrorMessage;
    attribute DOMString? ariaExpanded;
    attribute DOMString? ariaFlowTo;
    attribute DOMString? ariaHasPopup;
    attribute DOMString? ariaHidden;
    attribute DOMString? ariaInvalid;
    attribute DOMString? ariaKeyShortcuts;
    attribute DOMString? ariaLabel;
    attribute DOMString? ariaLabelledBy;
    attribute DOMString? ariaLevel;
    attribute DOMString? ariaLive;
    attribute DOMString? ariaModal;
    attribute DOMString? ariaMultiLine;
    attribute DOMString? ariaMultiSelectable;
    attribute DOMString? ariaOrientation;
    attribute DOMString? ariaOwns;
    attribute DOMString? ariaPlaceholder;
    attribute DOMString? ariaPosInSet;
    attribute DOMString? ariaPressed;
    attribute DOMString? ariaReadOnly;
    attribute DOMString? ariaRelevant;
    attribute DOMString? ariaRequired;
    attribute DOMString? ariaRoleDescription;
    attribute DOMString? ariaRowCount;
    attribute DOMString? ariaRowIndex;
    attribute DOMString? ariaRowSpan;
    attribute DOMString? ariaSelected;
    attribute DOMString? ariaSetSize;
    attribute DOMString? ariaSort;
    attribute DOMString? ariaValueMax;
    attribute DOMString? ariaValueMin;
    attribute DOMString? ariaValueNow;
    attribute DOMString? ariaValueText;
  Element implements AriaAttributes;

ARIA Attribute Reflection

User agents MUST reflect the following content attributes to each of the corresponding IDL attributes on Element instances.

IDL Attribute Reflected ARIA Content Attribute
ariaActiveDescendant aria-activedescendant
ariaAtomic aria-atomic
ariaAutoComplete aria-autocomplete
ariaBusy aria-busy
ariaChecked aria-checked
ariaColCount aria-colcount
ariaColIndex aria-colindex
ariaColSpan aria-colspan
ariaControls aria-controls
ariaCurrent aria-current
ariaDescribedBy aria-describedby
ariaDetails aria-details
ariaDisabled aria-disabled
ariaErrorMessage aria-errormessage
ariaExpanded aria-expanded
ariaFlowTo aria-flowto
ariaHasPopup aria-haspopup
ariaHidden aria-hidden
ariaInvalid aria-invalid
ariaKeyShortcuts aria-keyshortcuts
ariaLabel aria-label
ariaLabelledBy aria-labelledby
ariaLevel aria-level
ariaLive aria-live
ariaModal aria-modal
ariaMultiLine aria-multiline
ariaMultiSelectable aria-multiselectable
ariaOrientation aria-orientation
ariaOwns aria-owns
ariaPlaceholder aria-placeholder
ariaPosInSet aria-posinset
ariaPressed aria-pressed
ariaReadOnly aria-readonly
ariaRelevant aria-relevant
ariaRequired aria-required
ariaRoleDescription aria-roledescription
ariaRowCount aria-rowcount
ariaRowIndex aria-rowindex
ariaRowSpan aria-rowspan
ariaSelected aria-selected
ariaSetSize aria-setsize
ariaSort aria-sort
ariaValueMax aria-valuemax
ariaValueMin aria-valuemin
ariaValueNow aria-valuenow
ariaValueText aria-valuetext

Note: Attributes aria-dropeffect and aria-grabbed were deprecated in ARIA 1.1 and do not have corresponding IDL attributes.

Disambiguation Pattern

Though specification authors may make exceptions to this pattern, the following rules were used to disambiguate names and case of the IDL attributes listed above.

  • Any attribute name referencing concepts that are combinations of two or more words (such as "described by") becomes a camel-cased IDL attribute capitalizing each word boundary. For example, aria-describedby becomes ariaDescribedBy with both the D and B capitalized.
  • Likewise, any attribute name referencing concepts that can be hyphenated (such as "multi-selectable") becomes a camel-cased IDL attribute capitalizing each hyphenation boundary. For example, the only valid spelling for "multi-selectable" is hyphenated, so aria-multiselectable becomes ariaMultiSelectable with both the M and S capitalized.
  • When trusted dictionary sources list both hyphenated or non-hyphenated spellings (e.g. "multi-line" and "multiline" are both valid spellings) use the hyphenated version and apply the hyphenation rule above. For example, aria-multiline becomes ariaMultiLine with both the M and L capitalized.
  • If all trusted dictionary sources list a single spelling of a compound word with no spaces or hyphens, only the first letter of the term is capitalized. For example, neither “place-holder” nor “place holder” are considered valid spellings of the term “placeholder,” so aria-placeholder becomes ariaPlaceholder with only the P capitalized.
  • There are currently no acronym-based ARIA attributes, but if future attributes include acronym usage, attempt to match existing DOM conventions (e.g. ID becomes Id).

IDL Attribute Name Notes or Exceptions

Any notes or exceptions for specific attribute names will be listed here.

  • ariaPosInSet: The aria-posinset attribute refers to an item's position in a set (two words: "in set") rather than the "inset" of an item from the beginning of the collection. Therefore the IDL attribute name is ariaPosInSet with the P, I, and second S capitalized, not ariaPosInset.

Editor's Note: Should we make an exception on the spelling of "placeholder" and capitalize the H anyway? Some developers will expect this to be ariaPlaceHolder despite the fact that it's not a hyphenated word.

Example IDL Attribute Usage

The primary purpose of ARIA IDL attribute reflection is to ease JavaScript-based manipulation of values. The following examples demonstrate its usage.