<div class="e-buttongroup">
  <a class="e-btn" href="#0" id="newDialog">
    Open Custom Dialog
  </a>
</div>

<div class="e-buttongroup">
  <a class="e-btn" href="#0" id="newDialog">
    Open Custom Dialog
  </a>
</div>

const dialogNode = document.createElement('div');
dialogNode.innerHTML = `
  <div class="e-dialog__header">Dialog Title</div>
  <div class="e-dialog__content">Dialog content goes here.</div>
  <div class="e-dialog__footer">
    <button class="e-btn e-btn-borderless">Close</button>
  </div>
`;

let dialog;

document.getElementById('newDialog').addEventListener('click', function() {
  dialog = window.e.utils.v2.ui.dialog({ content: dialogNode });
  dialog.open();
});

dialogNode.querySelector('.e-btn').addEventListener('click', function() {
  dialog.close();
});