[navyo]

Using the IDPF Validator, my ePub failed with one error in content1.xhtml

Error while parsing file 'attribute "role" not allowed here; expected attribute "class", "dir", "id", "lang", "style", "title" or "xml:lang"

Here is the code:

<span role="heading" class="calibre1">

What should I do?
Thanks in advance.