examples/web/client.html

<html>

<head>
  <title>ESC POS</title>
  <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.0/css/bootstrap.min.css">
</head>

<body>
  <div class="container" style="width: 50%;">
    <h1>ESC POS</h1>
    <form onsubmit="handlePrint()">
      <div class=" form-group">
        <label>Server</label>
        <input class="form-control" id="server" value="http://localhost:4000">
      </div>
      <div class="form-group">
        <label>Text</label>
        <input class="form-control" id="text" value="Hello World!">
      </div>
      <button o class=" btn btn-primary">Print</button>
    </form>
  </div>
  <script src="https://unpkg.com/axios/dist/axios.min.js"></script>
</body>

</html>

<script>
  function handlePrint() {
    event.preventDefault()
    server = document.getElementById("server").value
    text = document.getElementById("text").value
    axios.post(`${server}/print`, { "text": text })
      .then(function (response) {
        alert(response.data.status)
      })
      .catch(function (error) {
        alert(error)
      });
  }
</script>