add props parameter to helpPopup.show

edit/beautify.js

@@ -113,9 +113,10 @@ function createBeautifyUI(scope, options) {
           },
         }, t(scope.length === 1 ? 'undo' : 'undoGlobal')),
       ]),
-    ]));
-
-  $('#help-popup').className = 'wide';
+    ]),
+    {
+      className: 'wide',
+    });
 
   $('.beautify-options').onchange = ({target}) => {
     const value = target.type === 'checkbox' ? target.checked : target.selectedIndex > 0;

edit/settings.js

@@ -27,8 +27,9 @@ function StyleSettings() {
       $create('button', {onclick: helpPopup.close}, t('confirmClose')),
       createInfo({title: t('autosaveNotice')}),
     ]),
-  ]));
-  $('#help-popup').className = 'style-settings-popup';
+  ]), {
+    className: 'style-settings-popup',
+  });
   moveFocus(ui, 0);
 
   function textToList(text) {

edit/util.js

@@ -7,19 +7,26 @@
 
 const helpPopup = {
 
-  show(title = '', body) {
+  /**
+   * @param {string} title - plain text
+   * @param {string|Node} body - Node, html or plain text
+   * @param {Node} [props] - DOM props for the popup element
+   * @returns {Element} the popup
+   */
+  show(title = '', body, props) {
     const div = $('#help-popup');
     const contents = $('.contents', div);
+    div.style = '';
     div.className = '';
     contents.textContent = '';
+    Object.assign(div, props);
     if (body) {
       contents.appendChild(typeof body === 'string' ? t.HTML(body) : body);
     }
     $('.title', div).textContent = title;
     $('.dismiss', div).onclick = helpPopup.close;
     window.on('keydown', helpPopup.close, true);
-    // reset any inline styles
-    div.style = 'display: block';
+    div.style.display = 'block';
     helpPopup.originalFocus = document.activeElement;
     return div;
   },
@@ -172,8 +179,7 @@ function createHotkeyInput(prefId, {buttons = true, onDone}) {
 
 /* exported showCodeMirrorPopup */
 function showCodeMirrorPopup(title, html, options) {
-  const popup = helpPopup.show(title, html);
-  popup.classList.add('big');
+  const popup = helpPopup.show(title, html, {className: 'big'});
 
   let cm = popup.codebox = CodeMirror($('.contents', popup), Object.assign({
     mode: 'css',