disabled.md

layout	tags
doc-api.html	shadow-dom, service, argument-options

ally.maintain.disabled

Disables any type of user interaction - including the ability to focus elements - essentially rendering elements inert.

Description

This allows an application to make sure no element other than the exempted can be focused. This is method is superior to the idea of trapping focus by intercepting Tab, because it allows cycling through the browser UI and is not as prone to break for spatial focus navigation (i.e. any sort of focus navigation that does not use the Tab key). The major benefit of disabling focus of elements is that in turn we do not have to meddle with the user's interaction to actually change focus - we can leave that to the browser.

Elements are disabled by ally.element.disabled and can be identified in the DOM by the attribute [data-ally-disabled="true"] to align with styling of other :disabled elements.

The proposed inert attribute was removed from HTML5, because people thought inert subtrees by way of the <dialog> element would suffice. While we believe it doesn't, the inert attribute would only have solved half of the problem, because there's no way to avoid inheriting the inert state onto children. This behavior can be observed in the Google Chrome Inert Attribute Polyfill.

ally.maintain.disabled observes DOM manipulations and automatically disables newly added elements when necessary.

Usage

var handle = ally.maintain.disabled({
  context: '.within-filter-selector',
  filter: '.except-filter-selector',
});

handle.disengage();

Arguments

Name	Type	Default	Description
context	<selector>	documentElement	The scope of the DOM in which to search. The first element of a collection is used.
filter	<selector>	null	The significant elements to exclude from being disabled.

Returns

A <service> interface, providing the handle.disengage() method to stop the service.

Throws

Examples

• EXAMPLE: ally.maintain.disabled Example

Notes

• NOTE: ShadowHosts are pierced and ShadowRoot content is made inert as well (except for closed shadow trees).
• NOTE: Internet Explorer 10 will not update changes made to elements within the inert sub-trees, because it does not support MutationObserver and Mutation Events are too much of a burden.
• WARNING: Any element not identified as focus relevant by ally.is.focusRelevant and not identified as only tabbable by ally.is.onlyTabbable is not made inert either. See the identified elements using strategy: "strict" compatibility table.

Related resources

• ally.maintain.hidden is a service hiding insignificant branches from the Accessibility Tree
• ally.query.focusable is used to identify the elements to disable
• ally.element.disabled is used to disable the elements

Contributing

• module source
• document source
• unit test