diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index 2aef832c..73ff4ee 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -486,8 +486,8 @@ function template_preprocess_datetime_wrapper(&$variables) {
   }
 
   $variables['required'] = FALSE;
-  // For required datetime fields a 'form-required' class is appended to the
-  // label attributes.
+  // For required datetime fields 'form-required' & 'js-form-required' classes
+  // are appended to the label attributes.
   if (!empty($element['#required'])) {
     $variables['required'] = TRUE;
   }
@@ -1596,6 +1596,7 @@ function template_preprocess_field_multiple_value_form(&$variables) {
     $order_class = $element['#field_name'] . '-delta-order';
     $header_attributes = new Attribute(array('class' => array('label')));
     if (!empty($element['#required'])) {
+      $header_attributes['class'][] = 'js-form-required';
       $header_attributes['class'][] = 'form-required';
     }
     $header = array(
diff --git a/core/misc/states.js b/core/misc/states.js
index 680e86e..780d348 100644
--- a/core/misc/states.js
+++ b/core/misc/states.js
@@ -522,12 +522,12 @@
       if (e.value) {
         var $label = $(e.target).attr({'required': 'required', 'aria-required': 'aria-required'}).closest('.form-item, .form-wrapper').find('label');
         // Avoids duplicate required markers on initialization.
-        if (!$label.hasClass('form-required').length) {
-          $label.addClass('form-required');
+        if (!$label.hasClass('js-form-required').length) {
+          $label.addClass('js-form-required form-required');
         }
       }
       else {
-        $(e.target).removeAttr('required aria-required').closest('.form-item, .form-wrapper').find('label.form-required').removeClass('form-required');
+        $(e.target).removeAttr('required aria-required').closest('.form-item, .form-wrapper').find('label.js-form-required').removeClass('js-form-required form-required');
       }
     }
   });
diff --git a/core/modules/datetime/src/Tests/DateTimeFieldTest.php b/core/modules/datetime/src/Tests/DateTimeFieldTest.php
index e2223dc..b7a2988 100644
--- a/core/modules/datetime/src/Tests/DateTimeFieldTest.php
+++ b/core/modules/datetime/src/Tests/DateTimeFieldTest.php
@@ -100,7 +100,7 @@ function testDateField() {
     // Display creation form.
     $this->drupalGet('entity_test/add');
     $this->assertFieldByName("{$field_name}[0][value][date]", '', 'Date element found.');
-    $this->assertFieldByXPath('//*[@id="edit-' . $field_name . '-wrapper"]/h4[contains(@class, "form-required")]', TRUE, 'Required markup found');
+    $this->assertFieldByXPath('//*[@id="edit-' . $field_name . '-wrapper"]/h4[contains(@class, "js-form-required")]', TRUE, 'Required markup found');
     $this->assertNoFieldByName("{$field_name}[0][value][time]", '', 'Time element not found.');
 
     // Submit a valid date and ensure it is accepted.
diff --git a/core/modules/field_ui/field_ui.js b/core/modules/field_ui/field_ui.js
index 3ee0dab..9247a9a 100644
--- a/core/modules/field_ui/field_ui.js
+++ b/core/modules/field_ui/field_ui.js
@@ -11,15 +11,16 @@
     attach: function (context) {
       var $form = $(context).find('#field-ui-field-storage-add-form').once('field_ui_add');
       if ($form.length) {
-        // Add a few 'form-required' css classes here. We can not use the Form API
-        // '#required' property because both label elements for "add new" and
-        // "re-use existing" can never be filled and submitted at the same time.
+        // Add a few 'js-form-required' and 'form-required 'css classes here. We
+        // can not use the Form API '#required' property because both label
+        // elements for "add new" and "re-use existing" can never be filled and
+        // submitted at the same time.
         // The actual validation will happen server-side.
         $form.find(
           '.form-item-label label,' +
           '.form-item-field-name label,' +
           '.form-item-existing-storage-label label')
-          .addClass('form-required');
+          .addClass('js-form-required form-required');
 
         var $newFieldType = $form.find('select[name="new_storage_type"]');
         var $existingStorageName = $form.find('select[name="existing_storage_name"]');
diff --git a/core/modules/image/src/Tests/ImageFieldValidateTest.php b/core/modules/image/src/Tests/ImageFieldValidateTest.php
index fa52d06..9b47d83 100644
--- a/core/modules/image/src/Tests/ImageFieldValidateTest.php
+++ b/core/modules/image/src/Tests/ImageFieldValidateTest.php
@@ -69,11 +69,11 @@ function testRequiredAttributes() {
     $this->uploadNodeImage($image, $field_name, 'article');
 
     // Look for form-required for the alt text.
-    $elements = $this->xpath('//label[@for="edit-' . $field_name . '-0-alt" and @class="form-required"]/following-sibling::input[@id="edit-' . $field_name . '-0-alt"]');
+    $elements = $this->xpath('//label[@for="edit-' . $field_name . '-0-alt" and @class="js-form-required form-required"]/following-sibling::input[@id="edit-' . $field_name . '-0-alt"]');
 
     $this->assertTrue(isset($elements[0]),'Required marker is shown for the required alt text.');
 
-    $elements = $this->xpath('//label[@for="edit-' . $field_name . '-0-title" and @class="form-required"]/following-sibling::input[@id="edit-' . $field_name . '-0-title"]');
+    $elements = $this->xpath('//label[@for="edit-' . $field_name . '-0-title" and @class="js-form-required form-required"]/following-sibling::input[@id="edit-' . $field_name . '-0-title"]');
 
     $this->assertTrue(isset($elements[0]), 'Required marker is shown for the required title text.');
 
diff --git a/core/modules/system/src/Tests/Form/ElementsLabelsTest.php b/core/modules/system/src/Tests/Form/ElementsLabelsTest.php
index db5dbee..cc3ce30 100644
--- a/core/modules/system/src/Tests/Form/ElementsLabelsTest.php
+++ b/core/modules/system/src/Tests/Form/ElementsLabelsTest.php
@@ -53,16 +53,16 @@ function testFormLabels() {
 
     // Exercise various defaults for textboxes and modifications to ensure
     // appropriate override and correct behavior.
-    $elements = $this->xpath('//label[@for="edit-form-textfield-test-title-and-required" and @class="form-required"]/following-sibling::input[@id="edit-form-textfield-test-title-and-required"]');
+    $elements = $this->xpath('//label[@for="edit-form-textfield-test-title-and-required" and @class="js-form-required form-required"]/following-sibling::input[@id="edit-form-textfield-test-title-and-required"]');
     $this->assertTrue(isset($elements[0]), 'Label precedes textfield, with required marker inside label.');
 
-    $elements = $this->xpath('//input[@id="edit-form-textfield-test-no-title-required"]/preceding-sibling::label[@for="edit-form-textfield-test-no-title-required" and @class="form-required"]');
+    $elements = $this->xpath('//input[@id="edit-form-textfield-test-no-title-required"]/preceding-sibling::label[@for="edit-form-textfield-test-no-title-required" and @class="js-form-required form-required"]');
     $this->assertTrue(isset($elements[0]), 'Label tag with required marker precedes required textfield with no title.');
 
     $elements = $this->xpath('//input[@id="edit-form-textfield-test-title-invisible"]/preceding-sibling::label[@for="edit-form-textfield-test-title-invisible" and @class="visually-hidden"]');
     $this->assertTrue(isset($elements[0]), 'Label preceding field and label class is visually-hidden.');
 
-    $elements = $this->xpath('//input[@id="edit-form-textfield-test-title"]/preceding-sibling::span[@class="form-required"]');
+    $elements = $this->xpath('//input[@id="edit-form-textfield-test-title"]/preceding-sibling::span[@class="js-form-required form-required"]');
     $this->assertFalse(isset($elements[0]), 'No required marker on non-required field.');
 
     $elements = $this->xpath('//input[@id="edit-form-textfield-test-title-after"]/following-sibling::label[@for="edit-form-textfield-test-title-after" and @class="option"]');
diff --git a/core/modules/system/src/Tests/Form/FormTest.php b/core/modules/system/src/Tests/Form/FormTest.php
index 18ef1ed..05d9390 100644
--- a/core/modules/system/src/Tests/Form/FormTest.php
+++ b/core/modules/system/src/Tests/Form/FormTest.php
@@ -97,7 +97,7 @@ function testRequiredFields() {
     $elements['file']['empty_values'] = $empty_strings;
 
     // Regular expression to find the expected marker on required elements.
-    $required_marker_preg = '@<.*?class=".*?form-required.*?">@';
+    $required_marker_preg = '@<.*?class=".*?js-form-required.*form-required.*?">@';
     // Go through all the elements and all the empty values for them.
     foreach ($elements as $type => $data) {
       foreach ($data['empty_values'] as $key => $empty) {
diff --git a/core/modules/system/templates/datetime-wrapper.html.twig b/core/modules/system/templates/datetime-wrapper.html.twig
index 443b5b3..62a4b9d 100644
--- a/core/modules/system/templates/datetime-wrapper.html.twig
+++ b/core/modules/system/templates/datetime-wrapper.html.twig
@@ -17,7 +17,7 @@
 #}
 {%
   set title_classes = [
-    required ? 'form-required',
+    required ? 'js-form-required',
   ]
 %}
 {% if title %}
diff --git a/core/modules/system/templates/fieldset.html.twig b/core/modules/system/templates/fieldset.html.twig
index ab6796c..f7af6fa 100644
--- a/core/modules/system/templates/fieldset.html.twig
+++ b/core/modules/system/templates/fieldset.html.twig
@@ -25,7 +25,7 @@
   {%
     set legend_span_classes = [
       'fieldset-legend',
-      required ? 'form-required',
+      required ? 'js-form-required',
     ]
   %}
   {#  Always wrap fieldset legends in a SPAN for CSS positioning. #}
diff --git a/core/modules/system/templates/form-element-label.html.twig b/core/modules/system/templates/form-element-label.html.twig
index 6ececd9..644b4bd 100644
--- a/core/modules/system/templates/form-element-label.html.twig
+++ b/core/modules/system/templates/form-element-label.html.twig
@@ -18,7 +18,7 @@
   set classes = [
     title_display == 'after' ? 'option',
     title_display == 'invisible' ? 'visually-hidden',
-    required ? 'form-required',
+    required ? 'js-form-required',
   ]
 %}
 {% if title is not empty or required -%}
diff --git a/core/themes/classy/templates/form/datetime-wrapper.html.twig b/core/themes/classy/templates/form/datetime-wrapper.html.twig
index 399dea2..e3f504b 100644
--- a/core/themes/classy/templates/form/datetime-wrapper.html.twig
+++ b/core/themes/classy/templates/form/datetime-wrapper.html.twig
@@ -16,6 +16,7 @@
 {%
   set title_classes = [
     'label',
+    required ? 'js-form-required',
     required ? 'form-required',
   ]
 %}
diff --git a/core/themes/classy/templates/form/fieldset.html.twig b/core/themes/classy/templates/form/fieldset.html.twig
index f7460cf..7eb65f9 100644
--- a/core/themes/classy/templates/form/fieldset.html.twig
+++ b/core/themes/classy/templates/form/fieldset.html.twig
@@ -23,6 +23,7 @@
   {%
     set legend_span_classes = [
       'fieldset-legend',
+      required ? 'js-form-required',
       required ? 'form-required',
     ]
   %}
diff --git a/core/themes/classy/templates/form/form-element-label.html.twig b/core/themes/classy/templates/form/form-element-label.html.twig
index 70ed96c..7c2f8f2 100644
--- a/core/themes/classy/templates/form/form-element-label.html.twig
+++ b/core/themes/classy/templates/form/form-element-label.html.twig
@@ -16,6 +16,7 @@
   set classes = [
     title_display == 'after' ? 'option',
     title_display == 'invisible' ? 'visually-hidden',
+    required ? 'js-form-required',
     required ? 'form-required',
   ]
 %}