与我编写的脚本相比，在不同的计算器上的计算不同

Question

单击div click时，div three的背景色应更改，然后在一秒钟后更改。我下面有添加类的代码，但样式未显示在页面上。

let temp = document.querySelector('.three');
document.querySelector('.clickhere').addEventListener('click', () => {
  temp.classList.add('.select');
  console.log(temp);
  setTimeout(function() {
    temp.classList.remove('.select');
    console.log(temp);
  }, 1000);
});

.one {
  background-color: red;
}

.two {
  background-color: green;
}

.three {
  background-color: blue;
}

.select {
  background-color: black;
}

.clickhere {
  background-color: yellow;
}

<div class="one">
  ONE
</div>
<div class="two">
  TWO
</div>
<div class="three">
  THREE
</div>
<div class="clickhere">
  CLICK HERE
</div>

Answer 1

更新了您的代码段，我只需要用.select替换select

重要的是，仅在使用jQuery选择css类之前使用句号，在添加新类并删除它时，应该像在div标记内那样写它的名称。

编辑：我刚刚看到问题已经在评论中得到了解答，感谢@maazadeeb！ ：）

let temp = document.querySelector('.three');
document.querySelector('.clickhere').addEventListener('click', () => {
  temp.classList.add('select');
  console.log(temp);
  setTimeout(function() {
    temp.classList.remove('select');
    console.log(temp);
  }, 1000);
});

.one {
  background-color: red;
}

.two {
  background-color: green;
}

.three {
  background-color: blue;
}

.select {
  background-color: black !important;
}

.clickhere {
  background-color: yellow;
}

<div class="one">
  ONE
</div>
<div class="two">
  TWO
</div>
<div class="three">
  THREE
</div>
<div class="clickhere">
  CLICK HERE
</div>

Answer 2

temp.classList.add（'。select'）;应该更新为temp.classList.add（'select'）;

let temp = document.querySelector('.three');
document.querySelector('.clickhere').addEventListener('click', () => {
    temp.classList.add('select');
    setTimeout(function () {
        temp.classList.remove('select');
    }, 1000);
});

.one {
  background-color: red;
}

.two {
  background-color: green;
}

.three {
  background-color: blue;
}

.select {
  background-color: black;
}

.clickhere {
  background-color: yellow;
}

.select {
  background: coral;
}

<div class="one">
    ONE
</div>
<div class="two">
    TWO
</div>
<div class="three">
    THREE
</div>
<div class="clickhere">
    CLICK HERE
</div>