Id attribute is unique
This rule checks that all
id attribute values on a single page are unique.
This conformance rule relates to:
id attribute specified on an HTML or SVG element.
The value of the attribute is unique across all other
id attributes specified on HTML or SVG elements that exist within the same document tree or shadow tree as the element on which the applicable
id attribute is specified.
There are currently no assumptions.
There are no major accessibility support issues known for this rule.
id within the document context
ids are unique within the document context
id in shadow DOM is for the same element as
id in light DOM
Several elements have identical
Elements of different types have identical
display: none on an element still makes it applicable to this rule
id on element
id not applicable to this rule
Elements included in the accessibility tree of platform specific accessibility APIs. Elements in the accessibility tree are exposed to assistive technologies, allowing users to interact with the elements in a way that meet the requirements of the individual user.
The general rules for when elements are included in the accessibility tree are defined in the core accessibility API mappings. For native markup languages, such as HTML and SVG, additional rules for when elements are [included in the accessibility tree] can be found in the HTML accessibility API mappings and the SVG accessibility API mappings.
Note: Users of assistive technologies might still be able to interact with elements that are not included in the accessibility tree. An example of this is a focusable element with an
aria-hiddenattribute with a value of
true. Such an element could still be interacted with using sequential keyboard navigation regardless of the assistive technologies used, even though the element would not be included in the accessibility tree.
Elements should be visible on the page, and also meet the requirements for color contrast and visibility when focused. For more details, check out:
Content perceivable through sight.
Content is considered visible if making it fully transparent would result in a difference in the pixels rendered for any part of the document that is currently within the viewport or can be brought into the viewport via scrolling.
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