Javascript implements continuous assignment_javascript skills

I recently came into contact with the project and had enough time. I went shopping online and accidentally discovered this problem online. The predicted results were very different from the real results.

Please see the code below

var a={n:1}
var b=a;
a.x=a={n:2}
console.log(a.x); 
console.log(b.x);
undefined
Object{n:2}

If we take the code apart and look at it, the result is exactly what we thought

var a={n:1}
var b=a;
a={n:2}；
a.x={n:2}
console.log(a.x);//Object{n:2}
console.log(b.x);//undefined

Analysis code:

a.x=a={n:2}

The assignment operation of js is right associative, the above is equivalent to a.x=(a={n:2})

The evaluation operation of js is from left to right (PS: After discussing with a colleague, he said it was from left to right, I thought it was from right to left, but I finally found out that I was wrong)

1) a.x=(final result in brackets)

After finding that the x attribute of a does not exist, add an attribute

2) Because we want to get the result in the brackets, then a.

3) Return to a={n:2} in the brackets, and the direction of a has changed

Javascript implements assigning value to href

document.getElementById("a").href=""; a是要添加超链接a的id，比如<a id='a' >信息提示</a>
<form action="" method="post" name="myform" >
<a href="" id=links >信息提示 </a >
</form >
<script >
document.getElementById("links").href="http://www.baidu.com";
</script >

The content of this code is to assign a value to href. The code is very simple.

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