diff --git a/web/viewer.js b/web/viewer.js
index 7250fa722..1be81e02c 100644
--- a/web/viewer.js
+++ b/web/viewer.js
@@ -128,6 +128,7 @@ var PDFView = {
   isViewerEmbedded: (window.parent !== window),
   idleTimeout: null,
   currentPosition: null,
+  url: '',
 
   // called once when the document is loaded
   initialize: function pdfViewInitialize() {