This rule assumes that Success Criterion 2.4.2 Page Titled does not require that a document only has one title element, nor that it is a child of the head element of a document. While this is invalid in HTML, the HTML 5.2 specification describes what should happen in case of multiple titles, and titles outside the head element. Because of this, neither of these validation issues causes a conformance problem for WCAG. Regardless of whether this is required by 2.4.2 Page Titled, failing this rule means the success criterion is not satisfied.
Accessibility Support
There are no major accessibility support issues known for this rule.
Background
This rule is only applicable to non-embedded HTML pages. HTML pages embedded into other documents, such as through iframe or object elements are not applicable because they are not web pages according to the definition in WCAG.
An element with a specific namespaceURI value from HTML namespaces. For example an "SVG element" is any element with the "SVG namespace", which is https://www.w3.org/2000/svg.
Namespaced elements are not limited to elements described in a specification. They also include custom elements. Elements such as a and title have a different namespace depending on where they are used. For example a title in an HTML page usually has the HTML namespace. When used in an svg element, a title element has the SVG namespace instead.
An outcome is a conclusion that comes from evaluating an ACT Rule on a test subject or one of its constituent test target. An outcome can be one of the three following types:
Inapplicable: No part of the test subject matches the applicability
Failed: A test target does not meet all expectations
Note: A rule has one passed or failed outcome for every test target. When there are no test targets the rule has one inapplicable outcome. This means that each test subject will have one or more outcomes.
Note: Implementations using the EARL10-Schema can express the outcome with the outcome property. In addition to passed, failed and inapplicable, EARL 1.0 also defined an incomplete outcome. While this cannot be the outcome of an ACT Rule when applied in its entirety, it often happens that rules are only partially evaluated. For example, when applicability was automated, but the expectations have to be evaluated manually. Such "interim" results can be expressed with the incomplete outcome.
This section is not part of the official rule. It is populated dynamically and not accounted for in the change history or the last modified date. This section will not be included in the rule when it is published on the W3C website.
