make sure that options is an object

@@ -333,7 +333,7 @@ var
       // use the URL specified in options if one was provided
       // use the URL specified in options if one was provided
       if (typeof options === 'string') {
       if (typeof options === 'string') {
         return options;
         return options;
-      } else if (options.url) {
+      } else if (options && options.url) {
         return options.url;
         return options.url;
       }
       }