Custom toolbar button

<textarea id="custom-toolbar-button">
  <p><img style="display: block; margin-left: auto; margin-right: auto;" title="Tiny Logo" src="https://www.tiny.cloud/docs/images/logos/android-chrome-256x256.png" alt="TinyMCE Logo" width="128" height="128" /></p>
  <h2 style="text-align: center;">Welcome to the TinyMCE editor demo!</h2>
  <p>Select a menu item from the listbox above and it will insert contents into the editor at the caret position.</p>

  <h2>Got questions or need help?</h2>
  <ul>
    <li>Our <a href="https://www.tiny.cloud/docs/">documentation</a> is a great resource for learning how to configure TinyMCE.</li>
    <li>Have a specific question? Try the <a href="https://stackoverflow.com/questions/tagged/tinymce" target="_blank" rel="noopener"><code>tinymce</code> tag at Stack Overflow</a>.</li>
    <li>We also offer enterprise grade support as part of <a href="https://www.tiny.cloud/pricing">TinyMCE premium plans</a>.</li>
  </ul>

  <h2>Found a bug?</h2>
  <p>If you think you have found a bug please create an issue on the <a href="https://github.com/tinymce/tinymce/issues">GitHub repo</a> to report it to the developers.</p>

  <h2>Finally ...</h2>
  <p>Don't forget to check out our other product <a href="http://www.plupload.com" target="_blank">Plupload</a>, your ultimate upload solution featuring HTML5 upload support.</p>
  <p>Thanks for supporting TinyMCE! We hope it helps you and your users create great content.
    <br>All the best from the TinyMCE team.</p>
</textarea>

tinymce.init({
  selector: 'textarea#custom-toolbar-button',
  toolbar: 'customInsertButton customDateButton',
  setup: function (editor) {

    editor.ui.registry.addButton('customInsertButton', {
      text: 'My Button',
      onAction: function (_) {
        editor.insertContent('&nbsp;<strong>It\'s my button!</strong>&nbsp;');
      }
    });

    var toTimeHtml = function (date) {
      return '<time datetime="' + date.toString() + '">' + date.toDateString() + '</time>';
    };

    editor.ui.registry.addButton('customDateButton', {
      icon: 'insert-time',
      tooltip: 'Insert Current Date',
      disabled: true,
      onAction: function (_) {
        editor.insertContent(toTimeHtml(new Date()));
      },
      onSetup: function (buttonApi) {
        var editorEventCallback = function (eventApi) {
          buttonApi.setDisabled(eventApi.element.nodeName.toLowerCase() === 'time');
        };
        editor.on('NodeChange', editorEventCallback);

        /* onSetup should always return the unbind handlers */
        return function (buttonApi) {
          editor.off('NodeChange', editorEventCallback);
        };
      }
    });
  },
  content_style: 'body { font-family:Helvetica,Arial,sans-serif; font-size:14px }'
});