diff --git a/lib/OpenLayers/Util.js b/lib/OpenLayers/Util.js
index fcf9bb9e55..6260212cc2 100644
--- a/lib/OpenLayers/Util.js
+++ b/lib/OpenLayers/Util.js
@@ -147,17 +147,21 @@ OpenLayers.Util.clearArray = function(array) {
  * obj - {Object}
  * 
  * Returns:
- * {Integer} The index at, which the object was found in the array.
+ * {Integer} The index at, which the first object was found in the array.
  *           If not found, returns -1.
  */
 OpenLayers.Util.indexOf = function(array, obj) {
-
-    for(var i=0, len=array.length; i<len; i++) {
-        if (array[i] == obj) {
-            return i;
+    // use the build-in function if available.
+    if (typeof array.indexOf == "function") {
+        return array.indexOf(obj);
+    } else {
+        for (var i = 0, len = array.length; i < len; i++) {
+            if (array[i] == obj) {
+                return i;
+            }
         }
+        return -1;   
     }
-    return -1;   
 };
 
 
diff --git a/tests/Util.html b/tests/Util.html
index 3a214afed1..2932f7a376 100644
--- a/tests/Util.html
+++ b/tests/Util.html
@@ -38,6 +38,14 @@
                     "getImagesLocation()" );
     }
 
+    function test_Util_IndexOf(t) {
+        t.plan( 3 );
+        var array = new Array(1, "bar");
+        t.eq(OpenLayers.Util.indexOf(array, 1), 0);
+        t.eq(OpenLayers.Util.indexOf(array, "bar"), 1);
+        t.eq(OpenLayers.Util.indexOf(array, "foo"), -1);
+    }
+
     function test_Util_Array(t) {
         t.plan( 2 );