diff --git a/chrome/content/zotero/lookup.js b/chrome/content/zotero/lookup.js
index 3ee559dc14..8d8e41d034 100644
--- a/chrome/content/zotero/lookup.js
+++ b/chrome/content/zotero/lookup.js
@@ -27,7 +27,7 @@
  * Handles UI for lookup panel
  * @namespace
  */
-const Zotero_Lookup = new function () {
+var Zotero_Lookup = new function () {
 	/**
 	 * Performs a lookup by DOI, PMID, or ISBN
 	 */