diff --git a/source/Ox/js/Collection.js b/source/Ox/js/Collection.js
index 92a024cc..d694b017 100644
--- a/source/Ox/js/Collection.js
+++ b/source/Ox/js/Collection.js
@@ -462,19 +462,25 @@ Ox.slice <f> Alias for <code>Array.prototype.slice.call</code>
 Ox.slice = function(value, start, stop) {
     return Array.prototype.slice.call(value, start, stop);
 };
-//IE8 returns an empty array if undefined is passed as start, stop
-//IE8 returns an array of nulls if a string is passed to Array.prototype.slice.call
-if(Ox.slice([1]).length == 0 || Ox.slice('a')[0] == null) {
+// IE8 returns an empty array if undefined is passed as stop
+// and an array of null values if a string is passed as value.
+// Firefox 3.6 returns an array of undefined values
+// if a string is passed as value.
+if (
+    Ox.slice([0]).length == 0
+    || Ox.slice('0')[0] === null
+    || Ox.slice('0')[0] === void 0
+) {
     Ox.slice = function(value, start, stop) {
-        if(Ox.typeOf(value) == 'string')
-            value = value.split('')
+        if (Ox.typeOf(value) == 'string') {
+            value = value.split('');
+        }
         return stop === void 0
             ? Array.prototype.slice.call(value, start)
             : Array.prototype.slice.call(value, start, stop);
     };
 }
 
-
 /*@
 Ox.some <f> Tests if one or more elements of a collection meet a given condition
     Unlike <code>[].some()</code>, <code>Ox.some()</code> works for arrays,