diff --git a/calendar/providers/storage/calStorageCalendar.js b/calendar/providers/storage/calStorageCalendar.js
index f7da67020c3..0b413122c3a 100644
--- a/calendar/providers/storage/calStorageCalendar.js
+++ b/calendar/providers/storage/calStorageCalendar.js
@@ -1649,9 +1649,9 @@ calStorageCalendar.prototype = {
 
         var tmp;
 
-        if (tmp = item.getUnproxiedProperty("CREATED"))
+        if ((tmp = item.getUnproxiedProperty("CREATED")))
             ip.time_created = tmp.nativeTime;
-        if (tmp = item.getUnproxiedProperty("LAST-MODIFIED"))
+        if ((tmp = item.getUnproxiedProperty("LAST-MODIFIED")))
             ip.last_modified = tmp.nativeTime;
 
         ip.title = item.getUnproxiedProperty("SUMMARY");