2.1.1 [WAI-ARIA1.0] Section 5.2.4 Inherited States and Properties


The specification states:

 States and properties are inherited from superclass roles in the role taxonomy, not from
 ancestor elements in the DOM tree. These properties are not explicitly defined on the role,
 as the inheritance of properties is automatic.

IE10 Mode and IE11 Mode (All Versions)

aria-readonly is not inherited.