学习css 伪类:has

学习抖音： @渡一前端提薪课

首先我们看下:has(selector)是什么

匹配包含（相对于 selector 的 :scope）指定选择器的元素。可以认为 selector 的前面有一个看不见的 :scope 伪类。它的强大之处是，可以实现父选择器和前面兄弟选择器的功能。支持所有的 CSS 选择符。

我们举个例子：

css

  .box1:has(p) {color: red;
}.box1:has(span) {color: blue;
}
.box1:has(a, div) {color: greenyellow;
}

html

<body><div class="box1"><p>ppp</p></div><div class="box1"><span>span</span></div><div class="box1"><a>有p</a></div><div class="box1"><div>有div</div></div>
</body>

结果，.box1:has(p) 就是包含 p 标签的.box1 元素。.box1:has(span)就是包含span的元素，.box1:has(a, div) 就是包换 a 和包含div的元素

进阶

知道这个原理后我们在进阶一下，看看子的伪类可不可以用。

css

.box1:has(.red:hover) {color: red;
}
.box1:has(.blue:hover) {color: blue;
}
.box1:has(.yellow:hover) {color: yellow;
}

html

<div class="box1"><div class="red">变红色</div><div class="blue">变蓝色</div><div class="yellow">变黄色</div>
</div>

结果：

基于这个特效我们做一个案例

案例

直接上代码

<!DOCTYPE html>
<html lang="en"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>demo-2</title><style>* {padding: 0;margin: 0;}.container {width: 400px;height: 400px;border: 2px solid #999;position: absolute;top: 100px;left: 50%;transform: translateX(-50%);display: grid;transition: 0.5s;grid-template-columns: 1fr 1fr 1fr;grid-template-rows: 1fr 1fr 1fr;gap: 5px}.item:nth-of-type(1) {background: red;}.item:nth-of-type(2) {background: rgb(255, 208, 0);}.item:nth-of-type(3) {background: rgb(0, 255, 0);}.item:nth-of-type(4) {background: rgb(166, 255, 0);}.item:nth-of-type(5) {background: rgb(170, 88, 224);}.item:nth-of-type(6) {background: rgba(0, 238, 255, 0.726);}.item:nth-of-type(7) {background: rgb(255, 115, 0);}.item:nth-of-type(8) {background: rgb(86, 75, 241);}.item:nth-of-type(9) {background: rgb(255, 0, 149);}.container:has(.item:nth-of-type(1):hover) {grid-template-columns: 2fr 1fr 1fr;grid-template-rows: 2fr 1fr 1fr;}.container:has(.item:nth-of-type(2):hover) {grid-template-columns: 1fr 2fr 1fr;grid-template-rows: 2fr 1fr 1fr;}.container:has(.item:nth-of-type(3):hover) {grid-template-columns: 1fr 1fr 2fr;grid-template-rows: 2fr 1fr 1fr;}.container:has(.item:nth-of-type(4):hover) {grid-template-columns: 2fr 1fr 1fr;grid-template-rows: 1fr 2fr 1fr;}.container:has(.item:nth-of-type(5):hover) {grid-template-columns: 1fr 2fr 1fr;grid-template-rows: 1fr 2fr 1fr;}.container:has(.item:nth-of-type(6):hover) {grid-template-columns: 1fr 1fr 2fr;grid-template-rows: 1fr 2fr 1fr;}.container:has(.item:nth-of-type(7):hover) {grid-template-columns: 2fr 1fr 1fr;grid-template-rows: 1fr 1fr 2fr;}.container:has(.item:nth-of-type(8):hover) {grid-template-columns: 1fr 2fr 1fr;grid-template-rows: 1fr 1fr 2fr;}.container:has(.item:nth-of-type(9):hover) {grid-template-columns: 1fr 1fr 2fr;grid-template-rows: 1fr 1fr 2fr;}</style>
</head><body><div class="container"><div class="item"></div><div class="item"></div><div class="item"></div><div class="item"></div><div class="item"></div><div class="item"></div><div class="item"></div><div class="item"></div><div class="item"></div></div>
</body>
<script>
</script></html>

效果：