//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());