HTML5 - Validation messages

What element should I use to show validation开发者_StackOverflow中文版 messages (errors) to the user? Which one is more semantic in HTML5?

You could consider adding an ARIA role of 'alert' or 'status'. I don't think that semantically any of the HTML elements is any better than <div class="error">

I typically would use a div with an error or notice class to show errors.

I would use javascript to show a javascript error box containing the erro(s).

EDIT: For server side validation we use a <div> that gets filled after an ajax call.