remove extend

Author: bobbykolev

02.jQuery/01.Slider/script.js

@@ -72,16 +72,4 @@ if (!Object.create) {
     f.prototype = obj;
     return new f();
   }
-}
-
-if (!Object.prototype.extend) {
-    Object.prototype.extend = function(properties) {
-        function f() {};
-        f.prototype = Object.create(this);
-        for(var prop in properties) {
-            f.prototype[prop] = properties[prop];
-        }
-        f.prototype._super = this;
-        return new f();
-    }
 }