diff --git a/core/lib/Drupal/Core/Ajax/AddJsCommand.php b/core/lib/Drupal/Core/Ajax/AddJsCommand.php
new file mode 100644
index 0000000..f7c0a8a
--- /dev/null
+++ b/core/lib/Drupal/Core/Ajax/AddJsCommand.php
@@ -0,0 +1,44 @@
+<?php
+
+namespace Drupal\Core\Ajax;
+
+/**
+ * An AJAX command for adding JS to the page via ajax.
+ *
+ * This command is implemented by Drupal.AjaxCommands.prototype.add_js()
+ * defined in misc/ajax.js.
+ *
+ * @see misc/ajax.js
+ *
+ * @ingroup ajax
+ */
+class AddJsCommand implements CommandInterface {
+
+  /**
+   * An array containing the attributes of the scripts to be added to the page.
+   *
+   * @var string[]
+   */
+  protected $styles;
+
+  /**
+   * Constructs an AddJsCommand.
+   *
+   * @param array $scripts
+   */
+  public function __construct($scripts) {
+    $this->styles = $scripts;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function render() {
+
+    return [
+      'command' => 'add_js',
+      'data' => $this->styles,
+    ];
+  }
+
+}
diff --git a/core/lib/Drupal/Core/Ajax/AjaxResponseAttachmentsProcessor.php b/core/lib/Drupal/Core/Ajax/AjaxResponseAttachmentsProcessor.php
index 45aa45e..6cb9f3e 100644
--- a/core/lib/Drupal/Core/Ajax/AjaxResponseAttachmentsProcessor.php
+++ b/core/lib/Drupal/Core/Ajax/AjaxResponseAttachmentsProcessor.php
@@ -174,11 +174,13 @@ protected function buildAttachmentsCommands(AjaxResponse $response, Request $req
     }
     if ($js_assets_header) {
       $js_header_render_array = $this->jsCollectionRenderer->render($js_assets_header);
-      $resource_commands[] = new PrependCommand('head', $this->renderer->renderPlain($js_header_render_array));
+      $scripts_attributes = array_map(function ($render_array) { return $render_array['#attributes']; }, $js_header_render_array);
+      $resource_commands[] = new AddJsCommand($scripts_attributes);
     }
     if ($js_assets_footer) {
       $js_footer_render_array = $this->jsCollectionRenderer->render($js_assets_footer);
-      $resource_commands[] = new AppendCommand('body', $this->renderer->renderPlain($js_footer_render_array));
+      $scripts_attributes = array_map(function ($render_array) { return $render_array['#attributes']; }, $js_footer_render_array);
+      $resource_commands[] = new AddJsCommand($scripts_attributes);
     }
     foreach (array_reverse($resource_commands) as $resource_command) {
       $response->addCommand($resource_command, TRUE);
diff --git a/core/misc/ajax.js b/core/misc/ajax.js
index fefe9f3..de5a418 100644
--- a/core/misc/ajax.js
+++ b/core/misc/ajax.js
@@ -859,14 +859,28 @@
     // Track if any command is altering the focus so we can avoid changing the
     // focus set by the Ajax command.
     var focusChanged = false;
-    for (var i in response) {
-      if (response.hasOwnProperty(i) && response[i].command && this.commands[response[i].command]) {
-        this.commands[response[i].command](this, response[i], status);
-        if (response[i].command === 'invoke' && response[i].method === 'focus') {
-          focusChanged = true;
+
+    var that = this;
+
+    Object.keys(response).reduce(function (deferredCommand, i) {
+      return deferredCommand.then(function () {
+        var command = response[i].command;
+        console.log('Excuted Command: ' + command);
+
+        if (command && that.commands[command]) {
+          if (command === 'invoke' && response[i].method === 'focus') {
+            focusChanged = true;
+          }
+
+          if (command === 'add_js') {
+            return that.commands[command](that, response[i], status);
+          }
+          else {
+            that.commands[command](that, response[i], status);
+          }
         }
-      }
-    }
+      });
+    }, $.Deferred().resolve());
 
     // If the focus hasn't be changed by the ajax commands, try to refocus the
     // triggering element or one of its parents if that element does not exist
@@ -1019,6 +1033,7 @@
       // our presets.
       var $wrapper = response.selector ? $(response.selector) : $(ajax.wrapper);
       var method = response.method || ajax.method;
+      console.log(method);
       var effect = ajax.getEffect(response);
       var settings;
 
@@ -1338,7 +1353,40 @@
           document.styleSheets[0].addImport(match[1]);
         } while (match);
       }
+    },
+
+    add_js: function (ajax, response, status) {
+      var deferred = $.Deferred();
+
+      // @todo: simplify JSON reponse and remove mapping?
+      var scriptsSrc = response.data.map(function (script) {
+        return script.src;
+      });
+
+      Drupal.drupalScriptLoader(scriptsSrc)
+        .fail(function () {
+          // @todo: error handler?
+        }).always(function () {
+          // @todo: simulated network delay on test purpose only, remove setTimeOut
+            deferred.resolve();
+        });
+
+      return deferred.promise();
     }
   };
 
+
+  // @todo: add into correct files.
+  // @todo: make it as slim conditional script loader. accept condition evelaution for futher loading. e.g. Let devleoper extend to load in IE only.
+  Drupal.drupalScriptLoader = function (scripts) {
+    return $.when.apply($, scripts.map(function (script) {
+      return $.ajax({
+        url: script,
+        dataType: 'script',
+        cache: true
+      });
+    }));
+  };
+
+
 })(jQuery, window, Drupal, drupalSettings);
diff --git a/core/misc/dialog/dialog.ajax.js b/core/misc/dialog/dialog.ajax.js
index 3f1b0c2..6b8f89d 100644
--- a/core/misc/dialog/dialog.ajax.js
+++ b/core/misc/dialog/dialog.ajax.js
@@ -5,6 +5,8 @@
 
 (function ($, Drupal) {
 
+  console.log('dialog.ajax.js loaded');
+
   'use strict';
 
   /**
@@ -111,6 +113,7 @@
    *   Returns false if there was no selector property in the response object.
    */
   Drupal.AjaxCommands.prototype.openDialog = function (ajax, response, status) {
+    console.log('openDialog() ajax command called');
     if (!response.selector) {
       return false;
     }