//擴展對象的count方法
Object.prototype.count = (
    Object.prototype.hasOwnProperty(‘__count__')
  ) ? function () {
    return this.__count__;
  } : function () {
    var count = 0;
    for (var i in this) if (this.hasOwnProperty(i)) {
      count ++;
    }
    return count;
  };

//使用
var myObj = {
    name1: “value1″,
    name2: “value2″
};

alert(myObj.count());