<a href="#" onclick="open_page('datetime')" class="w3-bar-item w3-button w3-hover-white">Date/Time</a>
<a href="#" onclick="open_page('wifi')" class="w3-bar-item w3-button w3-hover-white">WiFi</a>
<a href="#" onclick="open_page('shares')" class="w3-bar-item w3-button w3-hover-white">Shares</a>
<a href="#" onclick="open_page('datetime')" class="w3-bar-item w3-button w3-hover-white">Date/Time</a>
<a href="#" onclick="open_page('wifi')" class="w3-bar-item w3-button w3-hover-white">WiFi</a>
<a href="#" onclick="open_page('shares')" class="w3-bar-item w3-button w3-hover-white">Shares</a>