diff --git a/js/autocomplete.limit.js b/js/autocomplete.limit.js
index 18f1307..faefb69 100644
--- a/js/autocomplete.limit.js
+++ b/js/autocomplete.limit.js
@@ -1,27 +1,29 @@
 (function($) {
 
-  /**
-   * Keep an unmodified copy of the core search callback function.
-   */
-  Drupal.ACDB.prototype.coreSearch = Drupal.ACDB.prototype.search;
+  if (Drupal.ACDB) {
+    /**
+     * Keep an unmodified copy of the core search callback function.
+     */
+    Drupal.ACDB.prototype.coreSearch = Drupal.ACDB.prototype.search;
 
-  /**
-   * Override the search callback.
-   *
-   * Prevent autocomplete search from running if the search string is shorter
-   * than the limit. Otherwise, call the clone of the original search callback.
-   */
-  Drupal.ACDB.prototype.search = function (searchString) {
-    var limit = parseInt($(this.owner.input).data('limit') || Drupal.settings.autocomplete_limit.limit || 0, 10);
+    /**
+     * Override the search callback.
+     *
+     * Prevent autocomplete search from running if the search string is shorter
+     * than the limit. Otherwise, call the clone of the original search callback.
+     */
+    Drupal.ACDB.prototype.search = function (searchString) {
+      var limit = parseInt($(this.owner.input).data('limit') || Drupal.settings.autocomplete_limit.limit || 0, 10);
 
-    // Do not search if the string is too short.
-    if (limit && searchString.length < limit) {
-      return;
-    }
+      // Do not search if the string is too short.
+      if (limit && searchString.length < limit) {
+        return;
+      }
 
-    // Call the original core search callback.
-    return this.coreSearch(searchString);
-  };
+      // Call the original core search callback.
+      return this.coreSearch(searchString);
+    };
 
-  // Good night, and good luck.
+    // Good night, and good luck.
+  }
 })(jQuery);