diff --git a/core/modules/aggregator/src/Tests/AggregatorRenderingTest.php b/core/modules/aggregator/src/Tests/AggregatorRenderingTest.php
index dcdc4c0..4698072 100644
--- a/core/modules/aggregator/src/Tests/AggregatorRenderingTest.php
+++ b/core/modules/aggregator/src/Tests/AggregatorRenderingTest.php
@@ -101,7 +101,7 @@ public function testFeedPage() {
 
     // Check for presence of an aggregator pager.
     $this->drupalGet('aggregator');
-    $elements = $this->xpath("//ul[@class=:class]", array(':class' => 'pager__items'));
+    $elements = $this->xpath("//ul[@class=:class]", array(':class' => 'js-pager__items'));
     $this->assertTrue(!empty($elements), 'Individual source page contains a pager.');
 
     // Check for sources page title.
@@ -137,7 +137,7 @@ public function testFeedPage() {
 
     // Check for the presence of a pager.
     $this->drupalGet('aggregator/sources/' . $feed->id());
-    $elements = $this->xpath("//ul[@class=:class]", array(':class' => 'pager__items'));
+    $elements = $this->xpath("//ul[@class=:class]", array(':class' => 'js-pager__items'));
     $this->assertTrue(!empty($elements), 'Individual source page contains a pager.');
     $cache_tags = explode(' ', $this->drupalGetHeader('X-Drupal-Cache-Tags'));
     $this->assertTrue(in_array('aggregator_feed:' . $feed->id(), $cache_tags));
diff --git a/core/modules/contextual/contextual.module b/core/modules/contextual/contextual.module
index b7e8ef2..b87f941 100644
--- a/core/modules/contextual/contextual.module
+++ b/core/modules/contextual/contextual.module
@@ -31,7 +31,7 @@ function contextual_toolbar() {
       ),
     ),
     '#wrapper_attributes' => array(
-      'class' => array('hidden', 'contextual-toolbar-tab'),
+      'class' => array('hidden','js-contextual-toolbar-tab'),
     ),
     '#attached' => array(
       'library' => array(
diff --git a/core/modules/shortcut/src/Tests/ShortcutTranslationUITest.php b/core/modules/shortcut/src/Tests/ShortcutTranslationUITest.php
index 9f81cb5..01ab5ae 100644
--- a/core/modules/shortcut/src/Tests/ShortcutTranslationUITest.php
+++ b/core/modules/shortcut/src/Tests/ShortcutTranslationUITest.php
@@ -73,7 +73,7 @@ protected function doTestBasicTranslation() {
         $this->drupalGet('<front>', array('language' => $language));
         $expected_path = \Drupal::urlGenerator()->generateFromRoute('user.page', array(), array('language' => $language));
         $label = $entity->getTranslation($langcode)->label();
-        $elements = $this->xpath('//nav[contains(@class, "toolbar-lining")]/ul[@class="menu"]/li/a[contains(@href, :href) and normalize-space(text())=:label]', array(':href' => $expected_path, ':label' => $label));
+        $elements = $this->xpath('//nav[contains(@class, "js-toolbar-lining")]/ul[@class="menu"]/li/a[contains(@href, :href) and normalize-space(text())=:label]', array(':href' => $expected_path, ':label' => $label));
         $this->assertTrue(!empty($elements), format_string('Translated @language shortcut link @label found.', array('@label' => $label, '@language' => $language->getName())));
       }
     }
diff --git a/core/modules/system/src/Tests/Pager/PagerTest.php b/core/modules/system/src/Tests/Pager/PagerTest.php
index d7dd6b6..5eeb116 100644
--- a/core/modules/system/src/Tests/Pager/PagerTest.php
+++ b/core/modules/system/src/Tests/Pager/PagerTest.php
@@ -98,7 +98,7 @@ protected function testPagerQueryParametersAndCacheContext() {
    *   The current pager page the internal browser is on.
    */
   protected function assertPagerItems($current_page) {
-    $elements = $this->xpath('//ul[@class=:class]/li', array(':class' => 'pager__items'));
+    $elements = $this->xpath('//ul[@class=:class]/li', array(':class' => 'js-pager__items'));
     $this->assertTrue(!empty($elements), 'Pager found.');
 
     // Make current page 1-based.
diff --git a/core/modules/system/templates/pager.html.twig b/core/modules/system/templates/pager.html.twig
index 7ba4ff3..2f49bc3 100644
--- a/core/modules/system/templates/pager.html.twig
+++ b/core/modules/system/templates/pager.html.twig
@@ -34,7 +34,7 @@
 {% if items %}
   <nav class="pager" role="navigation" aria-labelledby="pagination-heading">
     <h4 id="pagination-heading" class="visually-hidden">{{ 'Pagination'|t }}</h4>
-    <ul class="pager__items">
+    <ul class="js-pager__items">
       {# Print first item if we are not on the first page. #}
       {% if items.first %}
         <li class="pager__item pager__item--first">
diff --git a/core/modules/views/js/ajax_view.js b/core/modules/views/js/ajax_view.js
index 3e0b680..ed9c257 100644
--- a/core/modules/views/js/ajax_view.js
+++ b/core/modules/views/js/ajax_view.js
@@ -28,7 +28,7 @@
    * Javascript object for a certain view.
    */
   Drupal.views.ajaxView = function (settings) {
-    var selector = '.view-dom-id-' + settings.view_dom_id;
+    var selector = '.js-view-dom-id-' + settings.view_dom_id;
     this.$view = $(selector);
 
     // Retrieve the path to use for views' ajax.
@@ -100,7 +100,7 @@
    * Attach the ajax behavior to each link.
    */
   Drupal.views.ajaxView.prototype.attachPagerAjax = function () {
-    this.$view.find('ul.pager__items > li > a, th.views-field a, .attachment .views-summary a')
+    this.$view.find('ul.js-pager__items > li > a, th.views-field a, .attachment .views-summary a')
       .each(jQuery.proxy(this.attachPagerLinkAjax, this));
   };
 
diff --git a/core/modules/views/src/Controller/ViewAjaxController.php b/core/modules/views/src/Controller/ViewAjaxController.php
index bd5f956..2608344 100644
--- a/core/modules/views/src/Controller/ViewAjaxController.php
+++ b/core/modules/views/src/Controller/ViewAjaxController.php
@@ -167,14 +167,14 @@ public function ajaxView(Request $request) {
 
         // Override the display's pager_element with the one actually used.
         if (isset($pager_element)) {
-          $response->addCommand(new ScrollTopCommand(".view-dom-id-$dom_id"));
+          $response->addCommand(new ScrollTopCommand(".js-view-dom-id-$dom_id"));
           $view->displayHandlers->get($display_id)->setOption('pager_element', $pager_element);
         }
         // Reuse the same DOM id so it matches that in drupalSettings.
         $view->dom_id = $dom_id;
 
         if ($preview = $view->preview($display_id, $args)) {
-          $response->addCommand(new ReplaceCommand(".view-dom-id-$dom_id", $this->renderer->render($preview)));
+          $response->addCommand(new ReplaceCommand(".js-view-dom-id-$dom_id", $this->renderer->render($preview)));
           $response->setAttachments($preview['#attached']);
         }
         return $response;
diff --git a/core/modules/views/src/Tests/Handler/AreaEntityTest.php b/core/modules/views/src/Tests/Handler/AreaEntityTest.php
index bc3fe6e..fc6b759 100644
--- a/core/modules/views/src/Tests/Handler/AreaEntityTest.php
+++ b/core/modules/views/src/Tests/Handler/AreaEntityTest.php
@@ -125,23 +125,26 @@ public function doTestRender($entities) {
     $view = Views::getView('test_entity_area');
     $preview = $view->preview('default', [$entities[1]->id()]);
     $this->setRawContent(\Drupal::service('renderer')->render($preview));
+    $view_class = 'js-view-dom-id-' . $view->dom_id;
+    $headers_xpath = '//div[@class = "' . $view_class . '"]/div[1]';
+    $footers_xpath = '//div[@class = "' . $view_class . '"]/div[3]';
 
-    $result = $this->xpath('//div[@class = "view-header"]');
+    $result = $this->xpath('$headers_xpath');
     $this->assertTrue(strpos(trim((string) $result[0]), $entities[0]->label()) !== FALSE, 'The rendered entity appears in the header of the view.');
     $this->assertTrue(strpos(trim((string) $result[0]), 'full') !== FALSE, 'The rendered entity appeared in the right view mode.');
 
-    $result = $this->xpath('//div[@class = "view-footer"]');
+    $result = $this->xpath('$footers_xpath');
     $this->assertTrue(strpos(trim((string) $result[0]), $entities[1]->label()) !== FALSE, 'The rendered entity appears in the footer of the view.');
     $this->assertTrue(strpos(trim((string) $result[0]), 'full') !== FALSE, 'The rendered entity appeared in the right view mode.');
 
     $preview = $view->preview('default', array($entities[1]->id()));
     $this->setRawContent(drupal_render($preview));
 
-    $result = $this->xpath('//div[@class = "view-header"]');
+    $result = $this->xpath('$headers_xpath"]');
     $this->assertTrue(strpos(trim((string) $result[0]), $entities[0]->label()) !== FALSE, 'The rendered entity appears in the header of the view.');
     $this->assertTrue(strpos(trim((string) $result[0]), 'full') !== FALSE, 'The rendered entity appeared in the right view mode.');
 
-    $result = $this->xpath('//div[@class = "view-footer"]');
+    $result = $this->xpath('$footers_xpath');
     $this->assertTrue(strpos(trim((string) $result[0]), $entities[1]->label()) !== FALSE, 'The rendered entity appears in the footer of the view.');
     $this->assertTrue(strpos(trim((string) $result[0]), 'full') !== FALSE, 'The rendered entity appeared in the right view mode.');
 
diff --git a/core/modules/views/src/Tests/ViewAjaxTest.php b/core/modules/views/src/Tests/ViewAjaxTest.php
index 1121f41..f7cda72 100644
--- a/core/modules/views/src/Tests/ViewAjaxTest.php
+++ b/core/modules/views/src/Tests/ViewAjaxTest.php
@@ -56,7 +56,7 @@ public function testAjaxView() {
 
     // Ensure that the view insert command is part of the result.
     $this->assertEqual($data[1]['command'], 'insert');
-    $this->assertTrue(strpos($data[1]['selector'], '.view-dom-id-') === 0);
+    $this->assertTrue(strpos($data[1]['selector'], '.js-view-dom-id-') === 0);
 
     $this->setRawContent($data[1]['data']);
     $result = $this->xpath('//div[contains(@class, "views-row")]');
diff --git a/core/modules/views/templates/views-exposed-form.html.twig b/core/modules/views/templates/views-exposed-form.html.twig
index f5b5fc3..3fdc576 100644
--- a/core/modules/views/templates/views-exposed-form.html.twig
+++ b/core/modules/views/templates/views-exposed-form.html.twig
@@ -18,6 +18,6 @@
   #}
 {{ q }}
 {% endif %}
-<div class="form--inline clearfix">
+<div>
   {{ form }}
 </div>
diff --git a/core/modules/views/templates/views-mini-pager.html.twig b/core/modules/views/templates/views-mini-pager.html.twig
index 480e1a3..2f36b16 100644
--- a/core/modules/views/templates/views-mini-pager.html.twig
+++ b/core/modules/views/templates/views-mini-pager.html.twig
@@ -12,11 +12,11 @@
  */
 #}
 {% if items.previous or items.next %}
-  <nav class="pager" role="navigation" aria-labelledby="pagination-heading">
-    <h4 class="pager__heading visually-hidden">{{ 'Pagination'|t }}</h4>
-    <ul class="pager__items">
+  <nav role="navigation" aria-labelledby="pagination-heading">
+    <h4 class="visually-hidden">{{ 'Pagination'|t }}</h4>
+    <ul class="js-pager__items">
       {% if items.previous %}
-        <li class="pager__item pager__item--previous">
+        <li>
           <a href="{{ items.previous.href }}" title="{{ 'Go to previous page'|t }}" rel="prev"{{ items.previous.attributes|without('href', 'title', 'rel') }}>
             <span class="visually-hidden">{{ 'Previous page'|t }}</span>
             <span aria-hidden="true">{{ items.previous.text|default('‹‹'|t) }}</span>
@@ -24,14 +24,14 @@
         </li>
       {% endif %}
       {% if items.current %}
-        <li class="pager__item is-active">
+        <li>
           {% trans %}
             Page {{ items.current }}
           {% endtrans %}
         </li>
       {% endif %}
       {% if items.next %}
-        <li class="pager__item pager__item--next">
+        <li>
           <a href="{{ items.next.href }}" title="{{ 'Go to next page'|t }}" rel="next"{{ items.next.attributes|without('href', 'title', 'rel') }}>
             <span class="visually-hidden">{{ 'Next page'|t }}</span>
             <span aria-hidden="true">{{ items.next.text|default('››'|t) }}</span>