indexsocket 2.html

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <title>Minimal working example</title>
</head>

<body>
  <ul id="events"></ul>

  <script src="/socket.io/socket.io.js"></script>
  <script>
    const $events = document.getElementById('events');

    const newItem = (content) => {
      const item = document.createElement('li');
      item.innerText = content;
      return item;
    };

    const socket = io();

    socket.on('connect', () => {
      $events.appendChild(newItem('connect'));
    });

    let counter = 0;
    setInterval(() => {
      ++counter;
      var sliderData = counter;
      socket.emit('hey', { counter }); // the object will be serialized for you
    }, 1000);
    //   socket.emit('Slider', sliderData);
    // }, 1000);
  </script>
</body>

</html>