diff --git includes/ajax.inc includes/ajax.inc
index 74b4e73..ba29a34 100644
--- includes/ajax.inc
+++ includes/ajax.inc
@@ -193,11 +193,39 @@
  *   functions.
  */
 function ajax_render($commands = array()) {
-  // Automatically extract any 'settings' added via drupal_add_js() and make
-  // them the first command.
+  // Automatically extract any scripts and settings that have been added via
+  // drupal_add_js() and create commands to pass that to the client.
   $scripts = drupal_add_js(NULL, NULL);
-  if (!empty($scripts['settings'])) {
-    array_unshift($commands, ajax_command_settings(call_user_func_array('array_merge_recursive', $scripts['settings']['data'])));
+  $default_query_string = variable_get('css_js_query_string', '0');
+  $js_version_string = variable_get('drupal_js_version_query_string', 'v=');
+
+  foreach ($scripts as $item) {
+    $query_string =  empty($item['version']) ? $default_query_string : $js_version_string . $item['version'];
+    switch ($item['type']) {
+      case 'setting':
+        $settings = $item['data'];
+        break;
+
+      case 'inline':
+        // Presently inline data is ignored.
+        break;
+
+      case 'file':
+        $query_string_separator = (strpos($item['data'], '?') !== FALSE) ? '&' : '?';
+        $js_files[] = file_create_url($item['data']) . $query_string_separator . ($item['cache'] ? $query_string : REQUEST_TIME);
+        break;
+
+      case 'external':
+        $js_files[] = $item['data'];
+        break;
+    }
+  }
+
+  if (!empty($settings)) {
+    array_unshift($commands, ajax_command_settings(call_user_func_array('array_merge_recursive', $settings)));
+  }
+  if (!empty($js_files)) {
+    array_unshift($commands, ajax_command_scripts($js_files));
   }
 
   // Allow modules to alter any AJAX response.
@@ -955,3 +983,27 @@ function ajax_command_restripe($selector) {
   );
 }
 
+/**
+ * Creates scripts command for the AJAX responder.
+ *
+ * This will add JavaScript files to the output. Files that have already
+ * been processed will not be processed again.
+ *
+ * This command is implemented by Drupal.ajax.prototype.commands.scripts()
+ * defined in misc/ajax.js.
+ *
+ * @param $files
+ *   The $files array is a simple array of filenames that match, exactly, the
+ *   scripts as they are added to the page or will be adde to the page in
+ *   the future.
+ *
+ * @return
+ *   An array suitable for use with the ajax_render() function.
+ */
+function ajax_command_scripts($files) {
+  return array(
+    'command' => 'scripts',
+    'files' => $files,
+  );
+}
+
diff --git includes/common.inc includes/common.inc
index 1066bdf..397258f 100644
--- includes/common.inc
+++ includes/common.inc
@@ -2108,7 +2108,7 @@ function url($path = NULL, array $options = array()) {
  * @param $path
  *   The internal path or external URL being linked to, such as "node/34" or
  *   "http://example.com/foo".
- * @return 
+ * @return
  *   Boolean TRUE or FALSE, where TRUE indicates an external path.
  */
 function url_is_external($path) {
@@ -3760,6 +3760,7 @@ function drupal_get_js($scope = 'header', $javascript = NULL) {
       'type' => 'text/javascript',
     ),
   );
+
   foreach ($items as $item) {
     $query_string =  empty($item['version']) ? $default_query_string : $js_version_string . $item['version'];
 
@@ -3785,11 +3786,11 @@ function drupal_get_js($scope = 'header', $javascript = NULL) {
 
       case 'file':
         $js_element = $element;
+        if ($item['defer']) {
+          $js_element['#attributes']['defer'] = 'defer';
+        }
+        $query_string_separator = (strpos($item['data'], '?') !== 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);
           $processed[$index++] = theme('html_tag', array('element' => $js_element));
         }
@@ -3799,6 +3800,8 @@ function drupal_get_js($scope = 'header', $javascript = NULL) {
           $key = 'aggregate' . $index;
           $processed[$key] = '';
           $files[$key][$item['data']] = $item;
+          $reported_files[] = file_create_url($item['data']) . $query_string_separator . ($item['cache'] ? $query_string : REQUEST_TIME);
+
         }
         break;
 
@@ -3827,6 +3830,13 @@ function drupal_get_js($scope = 'header', $javascript = NULL) {
         $processed[$key] = theme('html_tag', array('element' => $js_element));
       }
     }
+
+    // Report on the page the list of aggregated javascript files.
+    $js_element = $element;
+    $js_element['#value_prefix'] = $embed_prefix;
+    $js_element['#value'] = 'jQuery.extend(Drupal.ajaxFiles.scripts, ' . drupal_json_encode(drupal_map_assoc($reported_files)) . ");";
+    $js_element['#value_suffix'] = $embed_suffix;
+    $processed[] = theme('html_tag', array('element' => $js_element));
   }
 
   // Keep the order of JS files consistent as some are preprocessed and others are not.
@@ -6654,7 +6664,7 @@ function entity_form_field_validate($entity_type, $form, &$form_state) {
  * For some entity forms (e.g., forms with complex non-field data and forms that
  * simultaneously edit multiple entities), this behavior may be inappropriate,
  * so the #builder_function for such forms needs to implement the required
- * functionality instead of calling this function. 
+ * functionality instead of calling this function.
  */
 function entity_form_submit_build_entity($entity_type, $entity, $form, &$form_state) {
   $info = entity_get_info($entity_type);
diff --git misc/ajax.js misc/ajax.js
index 553d2cc..cfd1010 100644
--- misc/ajax.js
+++ misc/ajax.js
@@ -13,7 +13,13 @@
  * to provide AJAX capabilities.
  */
 
-Drupal.ajax = Drupal.ajax || {};
+Drupal.ajax = Drupal.ajax || { };
+
+/**
+ * Hold a list of files known to be on the page so that AJAX requests can
+ * safely add more.
+ */
+Drupal.ajaxFiles = Drupal.ajaxFiles|| { scripts: {}, css: {} };
 
 /**
  * Attaches the AJAX behavior to each AJAX form element.
@@ -427,6 +433,31 @@ Drupal.ajax.prototype.commands = {
   },
 
   /**
+   * Command to add scripts to the page.
+   *
+   * We keep a record of what CSS files are already on the page and attempt
+   * to avoid adding more.
+   */
+  scripts: function (ajax, response, status) {
+    // Build a list of scripts already loaded.
+    var scripts = {};
+    $('script').each(function () {
+      Drupal.ajaxFiles.scripts[this.src] = this.src;
+    });
+
+    var html = '';
+    for (var i in response.files) {
+      if (!Drupal.ajaxFiles.scripts[response.files[i]]) {
+        Drupal.ajaxFiles.scripts[response.files[i]] = response.files[i];
+        html += '<script type="text/javascript" src="' + response.files[i] + '"></script>';
+      }
+    }
+    if (html) {
+      $('html').prepend(html);
+    }
+  },
+
+  /**
    * Command to attach data using jQuery's data API.
    */
   data: function (ajax, response, status) {
diff --git modules/field/tests/field.test modules/field/tests/field.test
index 36d6284..99dd215 100644
--- modules/field/tests/field.test
+++ modules/field/tests/field.test
@@ -1439,7 +1439,7 @@ class FieldFormTestCase extends FieldTestCase {
     // Press 'add more' button through AJAX, and place the expected HTML result
     // as the tested content.
     $commands = $this->drupalPostAJAX(NULL, $edit, $this->field_name . '_add_more');
-    $this->content = $commands[1]['data'];
+    $this->content = $commands[2]['data'];
 
     for ($delta = 0; $delta <= $delta_range; $delta++) {
       $this->assertFieldByName("$this->field_name[$langcode][$delta][value]", $values[$delta], "Widget $delta is displayed and has the right value");
diff --git modules/poll/poll.test modules/poll/poll.test
index 0ca7aa8..9a10dab 100644
--- modules/poll/poll.test
+++ modules/poll/poll.test
@@ -342,7 +342,7 @@ class PollJSAddChoice extends DrupalWebTestCase {
     // Press 'add choice' button through AJAX, and place the expected HTML result
     // as the tested content.
     $commands = $this->drupalPostAJAX(NULL, $edit, array('op' => t('More choices')));
-    $this->content = $commands[1]['data'];
+    $this->content = $commands[2]['data'];
 
     $this->assertFieldByName('choice[chid:0][chtext]', $edit['choice[new:0][chtext]'], t('Field !i found', array('!i' => 0)));
     $this->assertFieldByName('choice[chid:1][chtext]', $edit['choice[new:1][chtext]'], t('Field !i found', array('!i' => 1)));
diff --git modules/simpletest/tests/ajax.test modules/simpletest/tests/ajax.test
index 2e10b80..82fbf4e 100644
--- modules/simpletest/tests/ajax.test
+++ modules/simpletest/tests/ajax.test
@@ -44,9 +44,9 @@ class AJAXFrameworkTestCase extends AJAXTestCase {
   function testAJAXRender() {
     $result = $this->drupalGetAJAX('ajax-test/render');
     // Verify that JavaScript settings are contained (always first).
-    $this->assertIdentical($result[0]['command'], 'settings', t('drupal_add_js() settings are contained first.'));
+    $this->assertIdentical($result[1]['command'], 'settings', t('drupal_add_js() settings are contained right after scripts.'));
     // Verify that basePath is contained in JavaScript settings.
-    $this->assertEqual($result[0]['settings']['basePath'], base_path(), t('Base path is contained in JavaScript settings.'));
+    $this->assertEqual($result[1]['settings']['basePath'], base_path(), t('Base path is contained in JavaScript settings.'));
   }
 
   /**
@@ -85,10 +85,10 @@ class AJAXCommandsTestCase extends AJAXTestCase {
     $commands = array();
     $commands[] = ajax_command_settings(array('foo' => 42));
     $result = $this->drupalGetAJAX('ajax-test/render', array('query' => array('commands' => $commands)));
-    // Verify that JavaScript settings are contained (always first).
-    $this->assertIdentical($result[0]['command'], 'settings', t('drupal_add_js() settings are contained first.'));
+    // Verify that JavaScript settings are contained (right after scripts).
+    $this->assertIdentical($result[1]['command'], 'settings', t('drupal_add_js() settings are contained right after scripts.'));
     // Verify that the custom setting is contained.
-    $this->assertEqual($result[1]['settings']['foo'], 42, t('Custom setting is output.'));
+    $this->assertEqual($result[2]['settings']['foo'], 42, t('Custom setting is output.'));
   }
 
   /**
@@ -286,7 +286,7 @@ class AJAXMultiFormTestCase extends AJAXTestCase {
         $button = $this->xpath($field_xpath . $button_xpath_suffix);
         $button_id = (string) $button[0]['id'];
         $commands = $this->drupalPostAJAX(NULL, array(), array($button_name => $button_value), 'system/ajax', array(), array(), $form_id, $settings['ajax'][$button_id]);
-        $settings = array_merge_recursive($settings, $commands[0]['settings']);
+        $settings = array_merge_recursive($settings, $commands[1]['settings']);
         $this->assert(count($this->xpath($field_xpath . $field_items_xpath_suffix)) == $i+2, t('Found the correct number of field items after an AJAX submission.'));
         $this->assertFieldByXPath($field_xpath . $button_xpath_suffix, NULL, t('Found the "add more" button after an AJAX submission.'));
         $this->assertNoDuplicateIds(t('Updated page contains unique IDs'), 'Other');