//扩展对象的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());