diff --git a/ItemRelationsPlugin.php b/ItemRelationsPlugin.php
index 5ba2dd1..ca43fd1 100644
--- a/ItemRelationsPlugin.php
+++ b/ItemRelationsPlugin.php
@@ -616,9 +616,6 @@ public function filterAdminNavigationMain($nav)
     public function filterAdminItemsFormTabs($tabs, $args)
     {
         $item = $args['item'];
-        echo "<script>
-                var itemRelationsSearchAndSelect = '".__('[Search and Select Below]')."';
-              </script>";
         $tabs['Item Relations'] = get_view()->itemRelationsForm($item);
         return $tabs;
     }
diff --git a/controllers/LookupController.php b/controllers/LookupController.php
index aa0fec9..8c56191 100644
--- a/controllers/LookupController.php
+++ b/controllers/LookupController.php
@@ -137,4 +137,56 @@ public function indexAction()
 
         $this->_helper->json($metadata);
     }
+
+    public function listItemTypesAction()
+    {
+        $itemTypesList = array(
+            '' => '- ' . __('All') . ' -',
+        );
+        $itemTypesList += $this->_getUsedItemTypes();
+        // Convert to a pseudo-associative array to keep order of ids.
+        $json = array(
+            'id' => array_keys($itemTypesList),
+            'label' => array_values($itemTypesList),
+        );
+        $this->_helper->json($json);
+    }
+
+    public function listCollectionsAction()
+    {
+        $collections = get_table_options('Collection');
+        // Convert to a pseudo-associative array to keep order of ids.
+        $json = array(
+            'id' => array_keys($collections),
+            'label' => array_values($collections),
+        );
+        $this->_helper->json($json);
+    }
+
+    /**
+     * Get the list of used item types for select form.
+     *
+     * @return array
+     */
+    protected function _getUsedItemTypes()
+    {
+        $db = get_db();
+
+        $itemTypesTable = $db->getTable('ItemType');
+        $itemTypesAlias = $itemTypesTable->getTableAlias();
+
+        $select = $itemTypesTable->getSelect()
+            ->reset(Zend_Db_Select::COLUMNS)
+            ->from(array(), array($itemTypesAlias . '.id', $itemTypesAlias . '.name'))
+            ->joinInner(array('items' => $db->Item), "items.item_type_id = $itemTypesAlias.id", array())
+            ->group($itemTypesAlias . '.id')
+            ->order($itemTypesAlias . '.name ASC');
+
+        $permissions = new Omeka_Db_Select_PublicPermissions('Items');
+        $permissions->apply($select, 'items');
+
+        $itemTypes = $db->fetchPairs($select);
+
+        return $itemTypes;
+    }
 }
diff --git a/views/helpers/ItemRelationsForm.php b/views/helpers/ItemRelationsForm.php
index a08b037..768347c 100644
--- a/views/helpers/ItemRelationsForm.php
+++ b/views/helpers/ItemRelationsForm.php
@@ -15,18 +15,11 @@ public function itemRelationsForm($item)
         $view = $this->view;
         $db = get_db();
 
-        // Prepare list of used item types for the select form.
-        $itemTypesList = array(
-            '-1' => '- ' . __('All') . ' -',
-        );
-        $itemTypesList += $this->_getUsedItemTypes();
-
         $html = $view->partial('common/item-relations-form.php', array(
             'item' => $item,
             'provideRelationComments' => get_option('item_relations_provide_relation_comments'),
             'formSelectProperties' => get_table_options('ItemRelationsProperty'),
             'allRelations' => ItemRelationsPlugin::prepareAllRelations($item),
-            'itemTypesList' => $itemTypesList,
         ));
 
         if (!defined("LITYLOADED")) {
@@ -35,36 +28,12 @@ public function itemRelationsForm($item)
           DEFINE("LITYLOADED", 1);
         }
         $html .= '<link href="' . css_src('item-relations') . '" rel="stylesheet">';
-        $html .= '<script type="text/javascript">var url = ' . json_encode(url('item-relations/lookup/')) . '</script>';
+        $html .= '<script type="text/javascript">';
+        $html .= 'var url = ' . json_encode(url('item-relations/lookup/')) . ';';
+        $html .= 'var itemRelationsSearchAndSelect = ' . json_encode(__('[Search and Select Below]')) . ';';
+        $html .= '</script>';
         $html .= js_tag('item-relations');
 
         return $html;
     }
-
-    /**
-     * Get the list of used item types for select form.
-     *
-     * @return array
-     */
-    protected function _getUsedItemTypes()
-    {
-        $db = get_db();
-
-        $itemTypesTable = $db->getTable('ItemType');
-        $itemTypesAlias = $itemTypesTable->getTableAlias();
-
-        $select = $itemTypesTable->getSelect()
-            ->reset(Zend_Db_Select::COLUMNS)
-            ->from(array(), array($itemTypesAlias . '.id', $itemTypesAlias . '.name'))
-            ->joinInner(array('items' => $db->Item), "items.item_type_id = $itemTypesAlias.id", array())
-            ->group($itemTypesAlias . '.id')
-            ->order($itemTypesAlias . '.name ASC');
-
-        $permissions = new Omeka_Db_Select_PublicPermissions('Items');
-        $permissions->apply($select, 'items');
-
-        $itemTypes = $db->fetchPairs($select);
-
-        return $itemTypes;
-    }
 }
diff --git a/views/shared/common/item-relations-form.php b/views/shared/common/item-relations-form.php
index 423423a..eb2315b 100644
--- a/views/shared/common/item-relations-form.php
+++ b/views/shared/common/item-relations-form.php
@@ -181,7 +181,7 @@
         </div>
         <div class="inputs nine columns omega">
             <?php echo $this->formSelect('new_relation_object_item_type_id',
-                null, array('multiple' => false), $itemTypesList); ?>
+                null, array('multiple' => false), array()); ?>
         </div>
     </div>
     <div class="field">
@@ -190,7 +190,7 @@
         </div>
         <div class="inputs nine columns omega">
             <?php echo $this->formSelect('new_relation_object_collection_id',
-                null, array('multiple' => false), get_table_options('Collection')); ?>
+                null, array('multiple' => false), array()); ?>
         </div>
     </div>
 
diff --git a/views/shared/javascripts/item-relations.js b/views/shared/javascripts/item-relations.js
index a2daf54..213a12f 100644
--- a/views/shared/javascripts/item-relations.js
+++ b/views/shared/javascripts/item-relations.js
@@ -83,6 +83,36 @@ jQuery(document).ready(function () {
                 }
             }
         });
+
+        // Update the list of item types.
+        $.ajax({
+            url: url + 'list-item-types',
+            dataType: 'json',
+            success: function (data) {
+                _loadList('select#new_relation_object_item_type_id', data);
+            }
+        });
+
+        // Update the list of collections.
+        $.ajax({
+            url: url + 'list-collections',
+            dataType: 'json',
+            success: function (data) {
+                _loadList('select#new_relation_object_collection_id', data);
+            }
+        });
+    }
+
+    function _loadList(element, data) {
+        var currentValue = $(element).val();
+        $(element).empty();
+        $.each(data['id'], function(i, id) {
+            $(element).append(
+                $('<option></option>')
+                    .val(id)
+                    .html(data['label'][i]));
+        });
+        $(element).val(currentValue);
     }
 
     function updateAddButton() {