diff --git a/lib/OpenLayers/Util.js b/lib/OpenLayers/Util.js
index 6fd439e561..fa6847470d 100644
--- a/lib/OpenLayers/Util.js
+++ b/lib/OpenLayers/Util.js
@@ -373,7 +373,7 @@ OpenLayers.Util.alphaHack = function() {
     // continue.
     
     try { 
-        filter = document.body.filters;
+        filter = !!(document.body.filters);
     } catch (e) {
     }