built-in prototype

  var properties=[
  "prototype",
  "toString", "valueOf", 
  "hasOwnProperty","isPrototypeOf",
  "propertyIsEnumerable","toLocaleString"
  ];
  for(var i in properties) {
    var key=properties[i];
    var val=Object.prototype[key];
    document.write(key+"=>"+val+"<br/>");
  }
  document.write("Object.prototype.prototype="+Object.prototype.prototype);