some more support for opera

source/Ox.js

@@ -142,6 +142,23 @@ if (!Array.prototype.reduce) {
     };
 }
 
+// see https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Object/keys
+if (!Object.keys) {
+    Object.keys = function(obj) {  
+        if (obj !== Object(obj)) {
+            throw new TypeError();  
+        }
+        var key,
+            ret = [];  
+        for (key in obj) {
+            if (Object.prototype.hasOwnProperty.call(obj, key)) {
+                ret.push(key);
+            }
+        }
+        return ret;
+    }
+}  
+
 //@ Core -----------------------------------------------------------------------
 
 /*@