Popup Error Example 5: aria-labelledby attribute used for error message
Features
aria-labelledby attribute is used to label form control and includes element with error message.
HTML5 required attribute to identify a form control is required.
aria-invalid="true" attribute is used to identify a form control has an invalid value, otherwise the attribute is removed for compatibility with Firefox.
role="status" is used to autmatically announce errors in form controls.