diff --git a/lib/OpenLayers/Marker.js b/lib/OpenLayers/Marker.js
index 318dbc0280..1375c54696 100644
--- a/lib/OpenLayers/Marker.js
+++ b/lib/OpenLayers/Marker.js
@@ -64,17 +64,13 @@ OpenLayers.Marker.prototype = {
      * @type Boolean
      */
     onScreen:function() {
-
-        var screenBounds = OpenLayers.Bounds.fromSize(this.map.getSize());  
-
-        var iconTop = parseInt(this.icon.div.style.top);
-        var iconLeft = parseInt(this.icon.div.style.left);
-        var iconBottom = iconTop + parseInt(this.icon.div.style.height);
-        var iconRight = iconLeft + parseInt(this.icon.div.style.width);
-        var iconBounds = 
-           new OpenLayers.Bounds(iconLeft, iconBottom, iconRight, iconTop);
-
-        return screenBounds.containsBounds(iconBounds, true);
+        
+        var onScreen = false;
+        if (this.map) {
+            var screenBounds = this.map.getExtent();
+            onScreen = screenBounds.contains(this.lonlat.lon, this.lonlat.lat);
+        }    
+        return onScreen;
     },
     
     /**