Untitled

<li>
  <a href="#" itemprop="url"><span itemprop="name">Link 1</span></a>
</li>

<li itemprop="name">
  <a href="#" itemprop="url">Link 1</a>
</li>

<!DOCTYPE html>
<html>
    <head>
        <title>test</title>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    </head>
    <body>
        <div itemscope itemtype="http://schema.org/WebPageElement">
            <link itemprop="additionalType" href="http://schema.org/ItemList" />
            <meta itemprop="name" content="navigation_menu" />
            <ul>
                <li itemprop="additionalType" itemscope itemtype="http://www.schema.org/SiteNavigationElement">
                    <span itemprop="itemListElement">
                        <a href="http://www.example.com/link_1" itemprop="url"><span itemprop="name">Link 1</span></a>
                    </span>
                </li>
                <li itemprop="additionalType" itemscope itemtype="http://www.schema.org/SiteNavigationElement">
                    <span itemprop="itemListElement">
                        <a href="http://www.example.com/link_2" itemprop="url"><span itemprop="name">Link 2</span></a>
                    </span>
                </li>
            </ul>
        </div>
    </body>
</html>