js中两个对象的比较

https://stackoverflow.com/questions/201183/how-to-determine-equality-for-two-javascript-objects

The default equality operator in JavaScript for Objects yields true when they refer to the same location in memory.
在JavaScript for Objects中，当它们引用内存中的相同位置时，默认的相等操作符会生成true。

var x = {};
var y = {};
var z = x;

x === y; // => false
x === z; // => true