If your web applications need to be more accessible to people with disabilities, the RadAjaxLoadingPanel control offers WAI-ARIA support, which a developer can easily enable by setting the EnableAriaSupport property to true. RadAjaxLoadingPanel WAI-ARIA attributes values are lower case.
An issue with the use of WAI-ARIA in HTML documents is that they don’t validate. When you run an HTML document containing WAI-ARIA attributes through the W3C Validator, it shows errors in the results for any WAI-ARIA attributes. The DOCTYPE declarations do not include any information about the WAI-ARIA attributes and you cannot have a valid document, which includes elements, attributes, and attribute values, not detailed in its DTD-s.