Use modern DOM methods a bit more (PR 15031 follow-up)

external/webL10n/l10n.js

@@ -27,6 +27,7 @@
  - Removes window._ assignment.
  - Remove compatibility code for OldIE.
  - Replaces `String.prototype.substr()` with `String.prototype.substring()`.
+ - Replaces one `Node.insertBefore()` with `Element.prepend()`.
  - Removes `fireL10nReadyEvent` since the "localized" event it dispatches
  is unused and may clash with an identically named event in the viewer.
 */
@@ -921,7 +922,7 @@ document.webL10n = (function(window, document, undefined) {
  // first element child.
  if (!found) {
  var textNode = document.createTextNode(data[gTextProp]);
- element.insertBefore(textNode, element.firstChild);
+ element.prepend(textNode);
  }
  }
  delete data[gTextProp];

src/display/annotation_layer.js

@@ -1499,7 +1499,7 @@ class ChoiceWidgetAnnotationElement extends WidgetAnnotationElement {
  noneOptionElement.value = " ";
  noneOptionElement.setAttribute("hidden", true);
  noneOptionElement.setAttribute("selected", true);
- selectElement.insertBefore(noneOptionElement, selectElement.firstChild);
+ selectElement.prepend(noneOptionElement);
 
  removeEmptyEntry = () => {
  noneOptionElement.remove();
@@ -1573,13 +1573,16 @@ class ChoiceWidgetAnnotationElement extends WidgetAnnotationElement {
  },
  insert(event) {
  const { index, displayValue, exportValue } = event.detail.insert;
+ const selectChild = selectElement.children[index];
  const optionElement = document.createElement("option");
  optionElement.textContent = displayValue;
  optionElement.value = exportValue;
- selectElement.insertBefore(
- optionElement,
- selectElement.children[index]
- );
+
+ if (selectChild) {
+ selectChild.before(optionElement);
+ } else {
+ selectElement.append(optionElement);
+ }
  storage.setValue(id, {
  value: getValue(event, /* isExport */ true),
  items: getItems(event),

web/base_tree_viewer.js

@@ -87,7 +87,7 @@ class BaseTreeViewer {
  this._toggleTreeItem(div, shouldShowAll);
  }
  };
- div.insertBefore(toggler, div.firstChild);
+ div.prepend(toggler);
  }
 
  /**

web/overlay_manager.js

@@ -51,7 +51,7 @@ class OverlayManager {
  const style = document.createElement("style");
  style.textContent = PDFJSDev.eval("DIALOG_POLYFILL_CSS");
 
- document.head.insertBefore(style, document.head.firstElementChild);
+ document.head.prepend(style);
  }
  }
 

web/text_highlighter.js

@@ -176,7 +176,7 @@ class TextHighlighter {
  let div = textDivs[divIdx];
  if (div.nodeType === Node.TEXT_NODE) {
  const span = document.createElement("span");
- div.parentNode.insertBefore(span, div);
+ div.before(span);
  span.append(div);
  textDivs[divIdx] = span;
  div = span;