luci/modules/luci-mod-admin-full/luasrc/view/admin_network/lease_status.htm

<script type="text/javascript">//<![CDATA[
	function duid2mac(duid) {
		// DUID-LLT / Ethernet
		if (duid.length === 28 && duid.substr(0, 8) === '00010001')
			return duid.substr(16).replace(/(..)(?=..)/g, '$1:').toUpperCase();

		// DUID-LL / Ethernet
		if (duid.length === 20 && duid.substr(0, 8) === '00030001')
			return duid.substr(8).replace(/(..)(?=..)/g, '$1:').toUpperCase();

		return null;
	}

	var hosts = <%=luci.http.write_json(luci.sys.net.host_hints())%>;

	XHR.poll(5, '<%=url('admin/network/dhcplease_status')%>', null,
		function(x, st)
		{
			var tb = document.getElementById('lease_status_table');
			if (st && st[0] && tb)
			{
				/* clear all rows */
				while (tb.firstElementChild !== tb.lastElementChild)
					tb.removeChild(tb.lastElementChild);

				for (var i = 0; i < st[0].length; i++)
				{
					var timestr;

					if (st[0][i].expires === false)
						timestr = '<em><%:unlimited%></em>';
					else if (st[0][i].expires <= 0)
						timestr = '<em><%:expired%></em>';
					else
						timestr = String.format('%t', st[0][i].expires);

					tb.appendChild(E('<div class="tr cbi-rowstyle-%d">'.format((i % 2) + 1), [
						E('<div class="td">', st[0][i].hostname || '?'),
						E('<div class="td">', st[0][i].ipaddr),
						E('<div class="td">', st[0][i].macaddr),
						E('<div class="td">', timestr)
					]));
				}

				if (tb.firstElementChild === tb.lastElementChild)
					tb.appendChild(E('<div class="tr"><div class="td"><em><br /><%:There are no active leases.%></em></div></div>'));
			}

			var tb6 = document.getElementById('lease6_status_table');
			if (st && st[1] && tb6)
			{
				tb6.parentNode.style.display = 'block';

				/* clear all rows */
				while (tb6.firstElementChild !== tb6.lastElementChild)
					tb6.removeChild(tb6.lastElementChild);

				for (var i = 0; i < st[1].length; i++)
				{
					var timestr;

					if (st[1][i].expires === false)
						timestr = '<em><%:unlimited%></em>';
					else if (st[1][i].expires <= 0)
						timestr = '<em><%:expired%></em>';
					else
						timestr = String.format('%t', st[1][i].expires);

					var host = hosts[duid2mac(st[1][i].duid)],
					    name = st[1][i].hostname,
					    hint = null;

					if (!name) {
						if (host)
							hint = host.name || host.ipv4 || host.ipv6;
					}
					else {
						if (host && host.name && st[1][i].hostname != host.name)
							hint = host.name;
					}

					tb6.appendChild(E('<div class="tr cbi-rowstyle-%d">'.format((i % 2) + 1), [
						E('<div class="td nowrap">', hint ? '%h (%h)'.format(name || '?', hint) : (name || '?')),
						E('<div class="td">', st[1][i].ip6addr),
						E('<div class="td">', st[1][i].duid),
						E('<div class="td">', timestr)
					]));
				}

				if (tb6.firstElementChild === tb6.lastElementChild)
					tb6.appendChild(E('<div class="tr"><div class="td"><em><br /><%:There are no active leases.%></em></div></div>'));
			}
		}
	);
//]]></script>

<fieldset class="cbi-section">
	<legend><%:Active DHCP Leases%></legend>
	<div class="table" id="lease_status_table">
		<div class="tr">
			<div class="th"><%:Hostname%></div>
			<div class="th"><%:IPv4-Address%></div>
			<div class="th"><%:MAC-Address%></div>
			<div class="th"><%:Leasetime remaining%></div>
		</div>
		<div class="tr">
			<div class="td" colspan="4"><em><br /><%:Collecting data...%></em></div>
		</div>
	</div>
</fieldset>

<fieldset class="cbi-section" style="display:none">
	<legend><%:Active DHCPv6 Leases%></legend>
	<div class="table" id="lease6_status_table">
		<div class="tr">
			<div class="th"><%:Host%></div>
			<div class="th"><%:IPv6-Address%></div>
			<div class="th"><%:DUID%></div>
			<div class="th"><%:Leasetime remaining%></div>
		</div>
		<div class="tr">
			<div class="td" colspan="4"><em><br /><%:Collecting data...%></em></div>
		</div>
	</div>
</fieldset>