diff --git a/includes/common.inc b/includes/common.inc
index 3e8d6d9..ba2df94 100644
--- a/includes/common.inc
+++ b/includes/common.inc
@@ -70,8 +70,7 @@ define('CSS_DEFAULT', 0);
 define('CSS_THEME', 100);
 
 /**
- * The default group for JavaScript libraries or jQuery plugins added to the
- * page.
+ * The default group for JavaScript and jQuery libraries added to the page.
  */
 define('JS_LIBRARY', -100);
 
@@ -4288,79 +4287,13 @@ function drupal_get_js($scope = 'header', $javascript = NULL, $skip_alter = FALS
     }
   }
 
-  // Sort the JavaScript so that it appears in the correct order.
-  uasort($items, 'drupal_sort_css_js');
-
-  // In Drupal 8, there's a JS_SETTING group for making setting variables
-  // appear last after libraries have loaded. In Drupal 7, this is forced
-  // without that group. We do not use the $key => $item type of iteration,
-  // because PHP uses an internal array pointer for that, and we're modifying
-  // the array order inside the loop.
-  foreach (array_keys($items) as $key) {
-    if ($items[$key]['type'] == 'setting') {
-      $item = $items[$key];
-      unset($items[$key]);
-      $items[$key] = $item;
-    }
-  }
-
-  // Provide the page with information about the individual JavaScript files
-  // used, information not otherwise available when aggregation is enabled.
-  $setting['ajaxPageState']['js'] = array_fill_keys(array_keys($items), 1);
-  unset($setting['ajaxPageState']['js']['settings']);
-  drupal_add_js($setting, 'setting');
-
-  // If we're outputting the header scope, then this might be the final time
-  // that drupal_get_js() is running, so add the setting to this output as well
-  // as to the drupal_add_js() cache. If $items['settings'] doesn't exist, it's
-  // because drupal_get_js() was intentionally passed a $javascript argument
-  // stripped of settings, potentially in order to override how settings get
-  // output, so in this case, do not add the setting to this output.
-  if ($scope == 'header' && isset($items['settings'])) {
-    $items['settings']['data'][] = $setting;
-  }
-
-  // Render the HTML needed to load the JavaScript.
-  $elements = array(
-    '#type' => 'scripts',
-    '#items' => $items,
-  );
-
-  return drupal_render($elements);
-}
-
-/**
- * #pre_render callback to add the elements needed for JavaScript tags to be rendered.
- *
- * This function evaluates the aggregation enabled/disabled condition on a group
- * by group basis by testing whether an aggregate file has been made for the
- * group rather than by testing the site-wide aggregation setting. This allows
- * this function to work correctly even if modules have implemented custom
- * logic for grouping and aggregating files.
- *
- * @param $element
- *   A render array containing:
- *   - #items: The JavaScript items as returned by drupal_add_js() and
- *     altered by drupal_get_js().
- *   - #group_callback: A function to call to group #items. Following
- *     this function, #aggregate_callback is called to aggregate items within
- *     the same group into a single file.
- *   - #aggregate_callback: A function to call to aggregate the items within
- *     the groups arranged by the #group_callback function.
- *
- * @return
- *   A render array that will render to a string of JavaScript tags.
- *
- * @see drupal_get_js()
- */
-function drupal_pre_render_scripts($elements) {
-  // Group and aggregate the items.
-  if (isset($elements['#group_callback'])) {
-    $elements['#groups'] = $elements['#group_callback']($elements['#items']);
-  }
-  if (isset($elements['#aggregate_callback'])) {
-    $elements['#aggregate_callback']($elements['#groups']);
-  }
+  $output = '';
+  // The index counter is used to keep aggregated and non-aggregated files in
+  // order by weight.
+  $index = 1;
+  $processed = array();
+  $files = array();
+  $preprocess_js = (variable_get('preprocess_js', FALSE) && (!defined('MAINTENANCE_MODE') || MAINTENANCE_MODE != 'update'));
 
   // A dummy query-string is added to filenames, to gain control over
   // browser-caching. The string changes on every update or full cache
@@ -4380,8 +4313,27 @@ function drupal_pre_render_scripts($elements) {
   // third-party code might require the use of a different query string.
   $js_version_string = variable_get('drupal_js_version_query_string', 'v=');
 
-  // Defaults for each SCRIPT element.
-  $element_defaults = array(
+  // Sort the JavaScript so that it appears in the correct order.
+  uasort($items, 'drupal_sort_css_js');
+
+  // Provide the page with information about the individual JavaScript files
+  // used, information not otherwise available when aggregation is enabled.
+  $setting['ajaxPageState']['js'] = array_fill_keys(array_keys($items), 1);
+  unset($setting['ajaxPageState']['js']['settings']);
+  drupal_add_js($setting, 'setting');
+
+  // If we're outputting the header scope, then this might be the final time
+  // that drupal_get_js() is running, so add the setting to this output as well
+  // as to the drupal_add_js() cache. If $items['settings'] doesn't exist, it's
+  // because drupal_get_js() was intentionally passed a $javascript argument
+  // stripped off settings, potentially in order to override how settings get
+  // output, so in this case, do not add the setting to this output.
+  if ($scope == 'header' && isset($items['settings'])) {
+    $items['settings']['data'][] = $setting;
+  }
+
+  // Loop through the JavaScript to construct the rendered output.
+  $element = array(
     '#type' => 'html_tag',
     '#tag' => 'script',
     '#value' => '',
@@ -4389,173 +4341,108 @@ function drupal_pre_render_scripts($elements) {
       'type' => 'text/javascript',
     ),
   );
+  foreach ($items as $item) {
+    $query_string =  empty($item['version']) ? $default_query_string : $js_version_string . $item['version'];
 
-  // Loop through each group.
-  foreach ($elements['#groups'] as $group) {
-    // If a group of files has been aggregated into a single file,
-    // $group['data'] contains the URI of the aggregate file. Add a single
-    // script element for this file.
-    if ($group['type'] == 'file' && isset($group['data'])) {
-      $element = $element_defaults;
-      $element['#attributes']['src'] = file_create_url($group['data']);
-      $element['#browsers'] = $group['browsers'];
-      $elements[] = $element;
-    }
-    // For non-file types, and non-aggregated files, add a script element per
-    // item.
-    else {
-      foreach ($group['items'] as $item) {
-        // Element properties that do not depend on item type.
-        $element = $element_defaults;
-        if (!empty($item['defer'])) {
-          $element['#attributes']['defer'] = 'defer';
-        }
-        $element['#browsers'] = $item['browsers'];
+    $js_element = $element;
 
-        // Element properties that depend on item type.
-        switch ($item['type']) {
-          case 'setting':
-            $element['#value_prefix'] = $embed_prefix;
-            $element['#value'] = 'jQuery.extend(Drupal.settings, ' . drupal_json_encode(drupal_array_merge_deep_array($item['data'])) . ");";
-            $element['#value_suffix'] = $embed_suffix;
-            break;
+    // Ensure browser defaults are populated.
+    $item['browsers'] += array(
+      'IE' => TRUE,
+      '!IE' => TRUE,
+    );
 
-          case 'inline':
-            $element['#value_prefix'] = $embed_prefix;
-            $element['#value'] = $item['data'];
-            $element['#value_suffix'] = $embed_suffix;
-            break;
+    // Generate a unique key that represents browsers so they can be grouped.
+    $browsers_key = ($item['browsers']['IE'] ? drupal_html_class($item['browsers']['IE']) : '0') . '_' . ($item['browsers']['!IE'] ? '1' : '0');
 
-          case 'file':
-            $query_string = empty($item['version']) ? $default_query_string : $js_version_string . $item['version'];
-            $query_string_separator = (strpos($item['data'], '?') !== FALSE) ? '&' : '?';
-            $element['#attributes']['src'] = file_create_url($item['data']) . $query_string_separator . ($item['cache'] ? $query_string : REQUEST_TIME);
-            break;
+    switch ($item['type']) {
+      case 'setting':
+        $js_element['#value_prefix'] = $embed_prefix;
+        $js_element['#value'] = 'jQuery.extend(Drupal.settings, ' . drupal_json_encode(drupal_array_merge_deep_array($item['data'])) . ");";
+        $js_element['#value_suffix'] = $embed_suffix;
+        $output .= drupal_render($js_element);
+        break;
 
-          case 'external':
-            $element['#attributes']['src'] = $item['data'];
-            break;
+      case 'inline':
+        if ($item['defer']) {
+          $js_element['#attributes']['defer'] = 'defer';
         }
+        $js_element['#value_prefix'] = $embed_prefix;
+        $js_element['#value'] = $item['data'];
+        $js_element['#value_suffix'] = $embed_suffix;
+        $js_element['#browsers'] = $item['browsers'];
+        $processed[$index++] = drupal_render($js_element);
+        break;
 
-        $elements[] = $element;
-      }
-    }
-  }
-
-  return $elements;
-}
-
-/**
- * Default callback to group JavaScript items.
- *
- * This function arranges the JavaScript items that are in the #items property
- * of the scripts element into groups. When aggregation is enabled, files within
- * a group are aggregated into a single file, significantly improving page
- * loading performance by minimizing network traffic overhead.
- *
- * This function puts multiple items into the same group if they are groupable
- * and if they are for the same browsers. Items of the 'file' type are groupable
- * if their 'preprocess' flag is TRUE. Items of the 'inline', 'settings', or
- * 'external' type are not groupable.
- *
- * This function also ensures that the process of grouping items does not change
- * their relative order. This requirement may result in multiple groups for the
- * same type and browsers, if needed to accommodate other items in
- * between.
- *
- * @param $javascript
- *   An array of JavaScript items, as returned by drupal_add_js(), but after
- *   alteration performed by drupal_get_js().
- *
- * @return
- *   An array of JavaScript groups. Each group contains the same keys (e.g.,
- *   'data', etc.) as a JavaScript item from the $javascript parameter, with the
- *   value of each key applying to the group as a whole. Each group also
- *   contains an 'items' key, which is the subset of items from $javascript that
- *   are in the group.
- *
- * @see drupal_pre_render_scripts()
- */
-function drupal_group_js($javascript) {
-  $groups = array();
-  // If a group can contain multiple items, we track the information that must
-  // be the same for each item in the group, so that when we iterate the next
-  // item, we can determine if it can be put into the current group, or if a
-  // new group needs to be made for it.
-  $current_group_keys = NULL;
-  $index = -1;
-  foreach ($javascript as $item) {
-    // The browsers for which the JavaScript item needs to be loaded is part of
-    // the information that determines when a new group is needed, but the order
-    // of keys in the array doesn't matter, and we don't want a new group if all
-    // that's different is that order.
-    ksort($item['browsers']);
-
-    switch ($item['type']) {
       case 'file':
-        // Group file items if their 'preprocess' flag is TRUE.
-        // Help ensure maximum reuse of aggregate files by only grouping
-        // together items that share the same 'group' value and 'every_page'
-        // flag. See drupal_add_js() for details about that.
-        $group_keys = $item['preprocess'] ? array($item['type'], $item['group'], $item['every_page'], $item['browsers']) : FALSE;
+        if (!$item['preprocess'] || !$preprocess_js) {
+          if ($item['defer']) {
+            $js_element['#attributes']['defer'] = 'defer';
+          }
+          $query_string_separator = (strpos($item['data'], '?') !== FALSE) ? '&' : '?';
+          $js_element['#attributes']['src'] = file_create_url($item['data']) . $query_string_separator . ($item['cache'] ? $query_string : REQUEST_TIME);
+          $js_element['#browsers'] = $item['browsers'];
+          // If item renders in all browsers, then there is no need for
+          // conditional comments. Increase and use the index as the key.
+          if ($item['browsers']['IE'] === TRUE && $item['browsers']['!IE']) {
+            $processed[$index++] = drupal_render($js_element);
+          }
+          // If item renders for specific browsers, group by browsers key and
+          // append each item so they are grouped properly.
+          else {
+            $processed[$browsers_key] = (!empty($processed[$browsers_key]) ? $processed[$browsers_key] : '') . drupal_render($js_element);
+          }
+        }
+        else {
+          // By increasing the index for each aggregated file, we maintain
+          // the relative ordering of JS by weight. We also set the key such
+          // that groups are split by items sharing the same 'group' value
+          // 'every_page' flag and browser conditions. While this potentially
+          // results in more aggregate files, it helps make each one more
+          // reusable across a site visit, leading to better front-end
+          // performance of a website as a whole. See drupal_add_js() for more
+          // details.
+          $key = $item['type'] . '_' . $item['every_page'] . '_' . $browsers_key . '_' . $index;
+          $processed[$key] = '';
+          $files[$key][$item['data']] = $item;
+        }
         break;
 
       case 'external':
-      case 'setting':
-      case 'inline':
-        // Do not group external, settings, and inline items.
-        $group_keys = FALSE;
+        // Preprocessing for external JavaScript files is ignored.
+        if ($item['defer']) {
+          $js_element['#attributes']['defer'] = 'defer';
+        }
+        $js_element['#attributes']['src'] = $item['data'];
+        $js_element['#browsers'] = $item['browsers'];
+        $processed[$index++] = drupal_render($js_element);
         break;
     }
-
-    // If the group keys don't match the most recent group we're working with,
-    // then a new group must be made.
-    if ($group_keys !== $current_group_keys) {
-      $index++;
-      // Initialize the new group with the same properties as the first item
-      // being placed into it. The item's 'data' and 'weight' properties are
-      // unique to the item and should not be carried over to the group.
-      $groups[$index] = $item;
-      unset($groups[$index]['data'], $groups[$index]['weight']);
-      $groups[$index]['items'] = array();
-      $current_group_keys = $group_keys ? $group_keys : NULL;
-    }
-
-    // Add the item to the current group.
-    $groups[$index]['items'][] = $item;
   }
 
-  return $groups;
-}
-
-/**
- * Default callback to aggregate JavaScript files.
- *
- * Having the browser load fewer JavaScript files results in much faster page
- * loads than when it loads many small files. This function aggregates files
- * within the same group into a single file unless the site-wide setting to do
- * so is disabled (commonly the case during site development). To optimize
- * download, it also compresses the aggregate files by removing comments,
- * whitespace, and other unnecessary content.
- *
- * @param $js_groups
- *   An array of JavaScript groups as returned by drupal_group_js(). For each
- *   group that is aggregated, this function sets the value of the group's
- *   'data' key to the URI of the aggregate file.
- *
- * @see drupal_group_js()
- * @see drupal_pre_render_scripts()
- */
-function drupal_aggregate_js(&$js_groups) {
-  // Only aggregate when the site is configured to do so, and not during an
-  // update.
-  if (variable_get('preprocess_js', FALSE) && (!defined('MAINTENANCE_MODE') || MAINTENANCE_MODE != 'update')) {
-    foreach ($js_groups as $key => $group) {
-      if ($group['type'] == 'file' && $group['preprocess']) {
-        $js_groups[$key]['data'] = drupal_build_js_cache($group['items']);
+  // Aggregate any remaining JS files that haven't already been output.
+  if ($preprocess_js && count($files) > 0) {
+    foreach ($files as $key => $file_set) {
+      $uri = drupal_build_js_cache($file_set);
+      // Only include the file if was written successfully. Errors are logged
+      // using watchdog.
+      if ($uri) {
+        $preprocess_file = file_create_url($uri);
+        $js_element = $element;
+        $js_element['#attributes']['src'] = $preprocess_file;
+        // The key contains browsers array as part of it's unique value, use
+        // the first file set's value for this preprocessed version.
+        $file_set_values = array_values($file_set);
+        $item = array_shift($file_set_values);
+        $js_element['#browsers'] = $item['browsers'];
+        $processed[$key] = drupal_render($js_element);
       }
     }
   }
+
+  // Keep the order of JS files consistent as some are preprocessed and others are not.
+  // Make sure any inline or JS setting variables appear last after libraries have loaded.
+  return implode('', $processed) . $output;
 }
 
 /**
@@ -5095,10 +4982,10 @@ function drupal_build_js_cache($files) {
 
   if (empty($uri) || !file_exists($uri)) {
     // Build aggregate JS file.
-    foreach ($files as $info) {
+    foreach ($files as $path => $info) {
       if ($info['preprocess']) {
         // Append a ';' and a newline after each JS file to prevent them from running together.
-        $contents .= file_get_contents($info['data']) . ";\n";
+        $contents .= file_get_contents($path) . ";\n";
       }
     }
     // Prefix filename to prevent blocking by firewalls which reject files
diff --git a/modules/simpletest/tests/common.test b/modules/simpletest/tests/common.test
index fc526cb..64131f3 100644
--- a/modules/simpletest/tests/common.test
+++ b/modules/simpletest/tests/common.test
@@ -1456,30 +1456,96 @@ class JavaScriptTestCase extends DrupalWebTestCase {
     drupal_add_js('misc/authorize.js', array('every_page' => TRUE));
     drupal_add_js('misc/autocomplete.js');
     drupal_add_js('misc/batch.js', array('every_page' => TRUE));
+    drupal_add_js('misc/collapse.js', array('browsers' => array(
+      'IE' => 'lt IE 8',
+      '!IE' => FALSE,
+    )));
+    drupal_add_js('misc/states.js', array('browsers' => array(
+      'IE' => 'lte IE 6',
+      '!IE' => FALSE,
+    )));
+    drupal_add_js('misc/textarea.js', array('browsers' => array(
+      'IE' => 'gt IE 7',
+      '!IE' => TRUE,
+    )));
+    drupal_add_js('misc/progress.js', array('browsers' => array(
+      'IE' => 'lt IE 8',
+      '!IE' => FALSE,
+    )));
     $javascript = drupal_get_js();
     $expected = implode("\n", array(
       '<script type="text/javascript" src="' . file_create_url('misc/authorize.js') . '?' . $default_query_string . '"></script>',
       '<script type="text/javascript" src="' . file_create_url('misc/batch.js') . '?' . $default_query_string . '"></script>',
       '<script type="text/javascript" src="' . file_create_url('misc/ajax.js') . '?' . $default_query_string . '"></script>',
       '<script type="text/javascript" src="' . file_create_url('misc/autocomplete.js') . '?' . $default_query_string . '"></script>',
+      "\n<!--[if lt IE 8]>",
+      '<script type="text/javascript" src="' . file_create_url('misc/collapse.js') . '?' . $default_query_string . '"></script>',
+      "<![endif]-->\n",
+      "<!--[if lt IE 8]>",
+      '<script type="text/javascript" src="' . file_create_url('misc/progress.js') . '?' . $default_query_string . '"></script>',
+      "<![endif]-->\n",
+      "<!--[if lte IE 6]>",
+      '<script type="text/javascript" src="' . file_create_url('misc/states.js') . '?' . $default_query_string . '"></script>',
+      "<![endif]-->\n",
+      "<!--[if gt IE 7]><!-->",
+      '<script type="text/javascript" src="' . file_create_url('misc/textarea.js') . '?' . $default_query_string . '"></script>',
+      "<!--<![endif]-->",
     ));
-    $this->assertTrue(strpos($javascript, $expected) > 0, t('Unaggregated JavaScript is added in the expected group order.'));
+    $this->assertTrue(strpos($javascript, $expected) !== FALSE, t('Unaggregated JavaScript is added in the expected group order.'));
 
-    // Now ensure that with aggregation on, one file is made for the
-    // 'every_page' files, and one file is made for the others.
-    drupal_static_reset('drupal_add_js');
+    // Enable aggregation.
     variable_set('preprocess_js', 1);
+
+    // Ensure a file is made for the 'every_page' files, one for different
+    // browser conditions and another for the rest.
+    drupal_static_reset('drupal_add_js');
+
+    // drupal_add_js() adds jquery.js, jquery.once.js and drupal.js if it's
+    // array is empty. This affects expect aggregation values, inject a fake
+    // settings array so they don't get added.
+    $settings = drupal_js_defaults(array());
+    $settings['type'] = 'setting';
+    $settings['group'] = JS_LIBRARY;
+    $drupal_add_js = &drupal_static('drupal_add_js', array());
+    $drupal_add_js['settings'] = $settings;
+
+    // Duplicate order and options above, but check for aggregated values.
     drupal_add_js('misc/ajax.js');
     drupal_add_js('misc/authorize.js', array('every_page' => TRUE));
     drupal_add_js('misc/autocomplete.js');
     drupal_add_js('misc/batch.js', array('every_page' => TRUE));
+    drupal_add_js('misc/collapse.js', array('browsers' => array(
+      'IE' => 'lt IE 8',
+      '!IE' => FALSE,
+    )));
+    drupal_add_js('misc/states.js', array('browsers' => array(
+      'IE' => 'lte IE 6',
+      '!IE' => FALSE,
+    )));
+    drupal_add_js('misc/textarea.js', array('browsers' => array(
+      'IE' => 'gt IE 7',
+      '!IE' => TRUE,
+    )));
+    drupal_add_js('misc/progress.js', array('browsers' => array(
+      'IE' => 'lt IE 8',
+      '!IE' => FALSE,
+    )));
     $js_items = drupal_add_js();
     $javascript = drupal_get_js();
     $expected = implode("\n", array(
       '<script type="text/javascript" src="' . file_create_url(drupal_build_js_cache(array('misc/authorize.js' => $js_items['misc/authorize.js'], 'misc/batch.js' => $js_items['misc/batch.js']))) . '"></script>',
       '<script type="text/javascript" src="' . file_create_url(drupal_build_js_cache(array('misc/ajax.js' => $js_items['misc/ajax.js'], 'misc/autocomplete.js' => $js_items['misc/autocomplete.js']))) . '"></script>',
+      "\n<!--[if lt IE 8]>",
+      '<script type="text/javascript" src="' . file_create_url(drupal_build_js_cache(array('misc/collapse.js' => $js_items['misc/collapse.js'], 'misc/progress.js' => $js_items['misc/progress.js']))) . '"></script>',
+      "<![endif]-->\n",
+      "<!--[if lte IE 6]>",
+      '<script type="text/javascript" src="' . file_create_url(drupal_build_js_cache(array('misc/states.js' => $js_items['misc/states.js']))) . '"></script>',
+      "<![endif]-->\n",
+      "<!--[if gt IE 7]><!-->",
+      '<script type="text/javascript" src="' . file_create_url(drupal_build_js_cache(array('misc/textarea.js' => $js_items['misc/textarea.js']))) . '"></script>',
+      "<!--<![endif]-->",
     ));
-    $this->assertTrue(strpos($javascript, $expected) > 0, t('JavaScript is aggregated in the expected groups and order.'));
+    $this->assertTrue(strpos($javascript, $expected) !== FALSE, t('JavaScript is aggregated in the expected groups and order.'));
   }
 
   /**
diff --git a/modules/system/system.module b/modules/system/system.module
index bfeeb50..d4f3bc4 100644
--- a/modules/system/system.module
+++ b/modules/system/system.module
@@ -322,12 +322,6 @@ function system_element_info() {
     '#group_callback' => 'drupal_group_css',
     '#aggregate_callback' => 'drupal_aggregate_css',
   );
-  $types['scripts'] = array(
-    '#items' => array(),
-    '#pre_render' => array('drupal_pre_render_scripts'),
-    '#group_callback' => 'drupal_group_js',
-    '#aggregate_callback' => 'drupal_aggregate_js',
-  );
 
   // Input elements.
   $types['submit'] = array(