Customize wp_nav_menu

Hello,

I working on a multilingual website and i’m using polylang for that which I think is really good..

I have a problem in my footer menu, what I want to do is: Then you click any of the footer links I shall make a popup window with the content from the single.php. But stay on the same site under the popup window.

I have made it without wordpress, but I will like to use the wordpress because I it makes it easy to add polylang.

Is it possible to get the same output from wp_nav_menu as the code underneath?

<nav id="footer">
    <ul id="footer-nav">
       <li><a class="popup" data-url="/path-to-post/">LINK</a></li>
      <li><a class="popup" data-url="/path-to-post/">LINK</a></li>
   </ul>
</nav>

I really hope someone can help me on this..

Many thanks.