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Provide a description and the nature of the error message and how to correct it. Example: “Please provide the correct date of birth. The primary applicant must be 18 years of age or older”.
Provide Declare form controls as invalid and display inline error messages to let the user know right away when a form element has not been completed or filled out correctly (when form control loses keyboard focus).
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once the form control has lost focus, or there has been an adequate delay in key presses (a few seconds)
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Using ARIA to Create Accessible Inline Error Messages
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