var arr={
            name:'cheng',
            age:22
        };

Object.prototype.copy=function(){
    var result=new Object();
    function iterator(o,result){
        for(name in o){
            if(!(o[name] instanceof Object)){
                result[name]=o[name];            
            }else{
                arguments.callee(o[name],result[name]);
            }
             
        }
        return result;
    }
    iterator(this,result);
    
};
console.log(arr.copy());

Object.prototype.clone=function(obj){
    var newObj=obj?obj:new Object();
    for(var i in this)
    {
      var objType=typeof this[i];
      if(objType=='object' || (objType=='function' && this[i]!=this.clone))//clone这个函数不能进行克隆，否则会陷入无限递归
      {
        newObj[i] = this[i].clone();
      } 
      else {
        newObj[i]=this[i];
      }
    }
    return newObj;
}
  Array.prototype.clone=function(){
    var newArr=new Array();
    for(var i=0;i<=this.length-1;i++)
    {
       var itemi=this[i];
       if(typeof itemi=='object' || (typeof itemi=="function" && itemi!=this.clone)) 
         itemi= itemi.clone();//用递归克隆多级数组,根据对象类型自然会调用对应方法;
       newArr.push(itemi);
    }
    Object.prototype.clone.call(this,newArr);//按类型克隆对象后调用Object的clone方法克隆扩展成员;
    return newArr;
  }
  Date.prototype.clone=function(){
    var newDate=new Date(this.getTime());
    Object.prototype.clone.call(this,newDate);
    return newDate;
  }
  Function.prototype.clone=function(){
    eval("var newFun="+this.toString());//使用函数的代码字符串生成新函数对象
    Object.prototype.clone.call(this,newFun);
    return newFun;
  }