Object 类型的对象虽然有 toString 方法，但结果却是 [Object Object] 让人没法理解的字符。比如简单的对象：{name:"张三",age:20,canfly:true,sayHello:function(){alert("hello!")},hasPower:["fly","selfFix","autobuilding"]}，此对象的数据格式几乎涵盖了所有常见的数据格式（字符、数字、布尔、方法、数组），如果执行该对象的toString方法能还原描述此对象的原始字符串，将能更直观地展示对象。

ok，let's go

Object.prototype.toString = function(){
 var str = "";
 for (var key in this){
  if(key=="toJSONString")continue;
  if(!this[key] || this[key]==true){
   str += ","+key+":"+this[key];
  }else if(typeof this[key]=="number"){
   str += ","+key+":"+this[key]+"";
  }else if(typeof this[key] == "string"){
   str += ","+key+":\""+this[key]+"\"";
  }else if(typeof this[key]=="function"){
   str += ","+key+":"+this[key].toString();
  }else if(typeof this[key] == "object"){  
   if(this[key].constructor == Array){
    str += ","+key+":"+this[key].toJSONString();
   }else if(this[key].constructor == Object){
    str += ","+key+":"+this[key].toString();
   }
  }
  
 }
 return "{"+str.substring(1)+"}";
}

Array.prototype.toJSONString = function(){
 var str = "";
 for (var key=0; key<this.length; key++){
  if(typeof this[key]=="number"){
   str += ","+this[key];
  }else if(typeof this[key] == "string"){
   str += ",\""+this[key]+"\"";
  }else if(!this[key] || this[key]==true){
   str += ","+this[key];
  }else if(typeof this[key]=="function"){
   str += ","+this[key].toString();
  }else if(typeof this[key] == "object"){  
   if(this[key].constructor == Array){
    str += ","+ this[key].toJSONString();
   }else if(this[key].constructor == Object){
    str += ","+this[key].toString();
   }
  }
  
 }
 return "["+str.substring(1)+"]";
}

方法很简单，处理的数据格式也仅限于上面提到的几种JavaScript内置数据格式。上面的代码有两段，但不能分拆，互相有引用。