diff --git a/lib/OpenLayers/Util.js b/lib/OpenLayers/Util.js
index 69240d1e45..41edef870c 100644
--- a/lib/OpenLayers/Util.js
+++ b/lib/OpenLayers/Util.js
@@ -719,7 +719,7 @@ OpenLayers.Util.createDiv = function(id, px, sz, imgURL, position,
 
     //set generic properties
     if (!id) {
-        id = "OpenLayersDiv" + (Math.random() * 10000 % 10000);
+        id = "OpenLayersDiv" + Math.round(Math.random() * 10000);
     }
     if (!position) {
         position = "absolute";
@@ -754,7 +754,7 @@ OpenLayers.Util.createImage = function(id, px, sz, imgURL, position, border) {
 
     //set generic properties
     if (!id) {
-        id = "OpenLayersDiv" + (Math.random() * 10000 % 10000);
+        id = "OpenLayersDiv" + Math.round(Math.random() * 10000);
     }
     if (!position) {
         position = "relative";