code to copy into the demo

<form>
  <div>
    <label for="username">username</label>
    <input
      id="username"
      type="text"
      autocomplete="username"
    />
    <label for="password">password</label>
    <input
      id="password"
      type="password"
      autocomplete="new-password"
    />
  </div>
  <button id="send">send</button>
</form>

<script>
document.getElementById('send').addEventListener('click', (event) => {
  //event.preventDefault()
  console.log('test')
})
</script>