2 files changed, 3 insertions, 3 deletions
diff --git a/program/js/app.js b/program/js/app.js
index 70a4850e1..43e3dd40a 100644
--- a/program/js/app.js
+++ b/program/js/app.js
@@ -7680,7 +7680,7 @@ function rcube_webmail()
     if (plugin && plugin.enabledPlugin)
         return 1;
 
-    if (window.ActiveXObject) {
+    if ('ActiveXObject' in window) {
       try {
         if (axObj = new ActiveXObject("AcroPDF.PDF"))
           return 1;
@@ -7713,7 +7713,7 @@ function rcube_webmail()
     if (plugin && plugin.enabledPlugin)
         return 1;
 
-    if (window.ActiveXObject) {
+    if ('ActiveXObject' in window) {
       try {
         if (axObj = new ActiveXObject("ShockwaveFlash.ShockwaveFlash"))
           return 1;
diff --git a/program/js/common.js b/program/js/common.js
index 72a68bb8b..977eb9057 100644
--- a/program/js/common.js
+++ b/program/js/common.js
@@ -93,7 +93,7 @@ function roundcube_browser()
   this.xmlhttp_test = function()
   {
     var activeX_test = new Function("try{var o=new ActiveXObject('Microsoft.XMLHTTP');return true;}catch(err){return false;}");
-    this.xmlhttp = (window.XMLHttpRequest || (window.ActiveXObject && activeX_test()));
+    this.xmlhttp = window.XMLHttpRequest || (('ActiveXObject' in window) && activeX_test());
     return this.xmlhttp;
   };