I have a site-wide main menu, which I'm currently using <nav> for. I also have a submenu, which is right under the main nav and is different for every product on the site. What's the best practice to handle this?
Currently, I have a separate <div id="secondary-nav"> below the main nav. But since they're both within the <header> of the page, I was thinking about having a nested <nav> instead. Is this an OK practice in HTML5?