连续赋值（1）
1 var a = {n:1}; 2 var b = a;//{n:1) 3 a = {n:2}; 4 a.x = a; 5 console.log(a.x);// { n: 2, x: [Circular] } 6 console.log(b.x);// undefined
精品讲解地址：https://blog.csdn.net/lvchunai/article/details/93971409
连续赋值（2）
1 var a = {n:1}; 2 var b = a;//{n:1) 3 a.x = a = {n:2}; 4 console.log(a.x);//undefined 5 console.log(b.x);//{n:2}
精品的讲解地址：https://blog.csdn.net/weixin_34088583/article/details/89085477?utm_medium=distribute.pc_relevant.none-task-blog-BlogCommendFromBaidu-1.nonecase&depth_1-utm_source=distribute.pc_relevant.none-task-blog-BlogCommendFromBaidu-1.nonecase