How to set data-wrapperels="div"

How to set data-wrapperels="div"

Hello,
I am using jqm 1.3 and I am trying to set 
    <a href="#menu" data-role="button" data-iconpos="right" data-shadow="false" data-wrapperels="div">
        Link
    </a>
but jqm implements it as a <span>
I've been Googling for some time, but can't find info about it.
Can someone explain me how it works or paste me a link where I can get more info?
Thank you