一道非常有趣的JS题
<script>
var a = {n:1};
var b = a;
a.x = a = {n:2};
console.log(a.x);
console.log(b.x);
</script>
a.x是undefined
b.x是{n:2}的对象
<script>
var a = {n:1};
var b = a;
a.x = a = {n:2};
console.log(a.x);
console.log(b.x);
</script>
a.x是undefined
b.x是{n:2}的对象