HTML 5.1 2nd Edition

4.14. Disabled elements

An element is said to be actually disabled if it falls into one of the following categories:

• a button element that is disabled
• an input element that is disabled
• a select element that is disabled
• a textarea element that is disabled
• an optgroup element that has a disabled attribute
• an option element that is disabled
• a menuitem element that has a disabled attribute
• a fieldset element that is a disabled fieldset

This definition is used to determine what elements can be focused and which elements match the :disabled pseudo-class.