The RadWindow control has WAI-ARIA support which can be easily
enabled by setting EnableAriaSupport="true". By that, the aria atttributes will be automatically rendered in the dialog's wrapper element.
Optionally, you can adjust the aria-label,
and aria-describedby attributes by using the
DescribedBy properties in the AriaSettings tag.
You can find more information about WAI-ARIA support in RadWindow in the WAI-ARIA Support article.
Please, note that an issue with the use of WAI-ARIA in HTML documents is that they
don’t validate. When you run a HTML document containing ARIA attributes through
the W3C Validator it shows errors in the results for any ARIA attributes. The
HTML 4.01 specification and its DOCTYPE
declarations (DTD) Strict,
, do not include any information about the WAI ARIA attributes and
you cannot have a valid HTML 4.01 document which includes, elements, attributes,
and attribute values, not detailed in its DTD’s.
By specification, the first input in a dialog should get the focus
when the dialog is opened. This is done out of the box for the predefined dialogs
(radalert, radconfirm and radprompt) and for other RadWindows it should be done
by the developer.