2
.....
 $sqlContar = mysqli_query($conexao,"SELECT COUNT(*) AS ContarTeste FROM teste");
 $jmContar = mysqli_fetch_object($sqlContar);
?>
<html>
    <head>
        <title>Nome do Site</title>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <script src="https://code.jquery.com/jquery-2.1.3.min.js"></script>
      <script type="text/javascript">
        window.setInterval(function() {
            mudarTitulo();
        }, 1000);
        function mudarTitulo() {
            document.title = "("+<?php echo $jmContar->ContarTeste; ?>+") Nome do Site";
        }
       // setTimeout(mudarTitulo(), 1000);
</script>
    </head>
    <body>
    </body>
</html>
But it only works if I press the F5.
PHP runs only once, so it is not possible to do a new count using php this way... what you can do is send a request in ajax to fetch the values in php.
– Silvio Andorinha