dataset-attribute.html

<button 
  class="btn btn-primary"
  data-user-id="42"
  data-role="admin"
>
  View
</button>

<script>
  const button = document.querySelector('.btn.btn-primary');

  button.addEventListener('click', (event) => {
    const { userId, role } = event.currentTarget.dataset;

    console.log(userId); // "42"
    console.log(role);   // "admin"
  });
</script>