Javascript判断对象为空对象的方法

1. for in 循环判断
   var obj = {};
   var result = function() {
   for(var key in obj) {
   return false;
   }
   return true;
   }
2. 将json对象转化为json字符串，再判断该字符串是否为"{}"

var data = {};
var result = (JSON.stringify(data) == "{}");

3. jquery的isEmptyObject方法

var data = {};
var result = $.isEmptyObject(data);

4. Object.getOwnPropertyNames()方法

var data = {};
var arr = Object.getOwnPropertyNames(data);
alert(arr.length == 0);//true

5. ES6的Object.keys()方法

var data = {};
var arr = Object.keys(data);
alert(arr.length == 0);//true