DNA/healthcheck.html

## healthcheck.html
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <script>
    document.onreadystatechange = () => {
      if (document.readyState === 'complete') {
        let xhr = new XMLHttpRequest();
        let serverStatus = document.getElementById('serverStatus');

        xhr.open('HEAD', 'https://api.github.com/');
        xhr.timeout   = 2000;
        xhr.onload    = _ => serverStatus.innerText = 'ONLINE';
        xhr.onerror   = _ => serverStatus.innerText = 'OFFLINE';
        xhr.ontimeout = _ => serverStatus.innerText = 'OFFLINE';
        xhr.send();
      }
    };

  </script>
</head>
<body>
  Server status: <span id="serverStatus">checking...</span>
</body>
</html>
	<!DOCTYPE html>
	<html lang="en">
	<head>
	<meta charset="UTF-8">
	<meta name="viewport" content="width=device-width, initial-scale=1.0">
	<meta http-equiv="X-UA-Compatible" content="ie=edge">
	<title>Document</title>
	<script>
	document.onreadystatechange = () => {
	if (document.readyState === 'complete') {
	let xhr = new XMLHttpRequest();
	let serverStatus = document.getElementById('serverStatus');

	xhr.open('HEAD', 'https://api.github.com/');
	xhr.timeout = 2000;
	xhr.onload = _ => serverStatus.innerText = 'ONLINE';
	xhr.onerror = _ => serverStatus.innerText = 'OFFLINE';
	xhr.ontimeout = _ => serverStatus.innerText = 'OFFLINE';
	xhr.send();
	}
	};

	</script>
	</head>
	<body>
	Server status: <span id="serverStatus">checking...</span>
	</body>
	</html>