diff --git a/lib/OpenLayers/Map.js b/lib/OpenLayers/Map.js
index ba727f5189..f344a0b7f1 100644
--- a/lib/OpenLayers/Map.js
+++ b/lib/OpenLayers/Map.js
@@ -580,8 +580,8 @@ OpenLayers.Map = OpenLayers.Class({
  
         // Because Mozilla does not support the "resize" event for elements 
         // other than "window", we need to put a hack here. 
-        if (OpenLayers.String.contains(navigator.appName, "Microsoft")) {
-            // If IE, register the resize on the div
+        if (parseFloat(navigator.appVersion.split("MSIE")[1]) < 9) {
+            // If IE < 9, register the resize on the div
             this.events.register("resize", this, this.updateSize);
         } else {
             // Else updateSize on catching the window's resize