Accessibility Inspector for WCAG Evaluation

Basic Concepts and Terms

Rule
A low-level accessibility conformance requirement with numerous components, the most basic of which are a definition, an evaluation function, and result messages. When a rule is evaluated, it is assigned a rule result value.  List of current rules.
Target resources
The set of HTML elements to which a particular rule applies. These include familiar elements such as div, img and input, as well as a pseudo-element designated as page, which is a placeholder for the document element. When a rule is evaluated, each of its target resources is assigned an element result value.
Evaluation
The application of all evaluation functions of all rules in the selected ruleset to their corresponding target resources in a web page, and the subsequent collection of all evaluation results and messages, at both the rule and element levels, into a dataset.
Rule result
The aggregate result of a rule evaluation with respect to its target resources (all of its target elements and/or the entire page).
Element result
The result of a rule evaluation with respect to one of its target elements.
Rule scope
element: A WCAG requirement for a specific html element or an element with an ARIA role, property or state.  For example, an img element must have an alt attribute.
page: A WCAG requirement that applies to a feature of a web page.  For example, a web page must have a main landmark.
website: A WCAG requrement that applied to pages in a website.  For example, consistent navigational links in each web page.