CSS伪元素: 在元素之间添加样式

Question

使用CSS伪元素:after或:before清除元素之间的浮动是否可行？还是我可以通过其他方式清除<div class="float">和<section class="inner">之间的浮动？

HTML和CSS代码如下：

* {
  margin: 0;
  padding: 0;
}
*, *:before, *:after {
    box-sizing: border-box;
}
section.wrap {
  width: 100%;
}
section.wrap:after {
  content: '';
  display: block;
  clear: both;
}

div {
  width: 33.33%;
  height: 40px;
  background-color: powderblue;
  float: left;
  border-top: solid 0px white;
  border-right: solid 5px white;
  border-bottom: solid 5px white;
  border-left: solid 0px white;
}

div:nth-of-type(3n + 3) {
    border-right: 0;
}

<section class="wrap">
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>

    <!-- CLEAR FLOAT HERE -->

    <section class="inner">
        Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.
    </section>
</section>

- caramba

---

将 clear: left 添加到 .inner 类。 - Mr_Green

@Mr_Green！就是这样！您可以将其发布为答案，以便我接受。 - caramba

哎呀，这是你的愿望。但我不会将其发布为答案 :) - Mr_Green

Answer 1

使用 clear: both 或者 clear: left 可以达到清除浮动的效果：

.inner {
    clear: both;
}

- Johann Kratzik

Answer 2

您可以清除 section 的 :before

* {
  margin: 0;
  padding: 0;
}
*, *:before, *:after {
box-sizing: border-box;
}
section.wrap {
  width: 100%;
}
section.wrap:after {
  content: '';
  display: block;
  clear: both;
}
div {
  width: 33.33%;
  height: 40px;
  background-color: powderblue;
  float: left;
  border-top: solid 0px white;
  border-right: solid 5px white;
  border-bottom: solid 5px white;
  border-left: solid 0px white;
}

div:nth-of-type(3n + 3) {
border-right: 0;
}
.inner:before {
content: '';
display: block;
clear: both;
}

<section class="wrap">
<div class="float"></div>
<div class="float"></div>
<div class="float"></div>
<div class="float"></div>
<div class="float"></div>
<div class="float"></div>
<div class="float"></div>
<div class="float"></div>
<div class="float"></div>
<div class="float"></div>

<!-- CLEAR FLOAT HERE -->

<section class="inner">
    Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.
</section>
</section>

- Felix A J

Answer 3

您可以在内部区域之前添加clear:both，就像这样：

* {
  margin: 0;
  padding: 0;
}
*, *:before, *:after {
    box-sizing: border-box;
}
section.wrap {
  width: 100%;
}
section.inner:before {
  content: '';
  display: block;
  clear: both;
}

div {
  width: 33.33%;
  height: 40px;
  background-color: powderblue;
  float: left;
  border-top: solid 0px white;
  border-right: solid 5px white;
  border-bottom: solid 5px white;
  border-left: solid 0px white;
}

div:nth-of-type(3n + 3) {
    border-right: 0;
}

<section class="wrap">
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>

    <!-- CLEAR FLOAT HERE -->

    <section class="inner">
        Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.
    </section>
</section>

- Michał Szachniewicz

Answer 4

除了原来的问题，使用flexbox布局和order属性可以在子元素之间放置::before/::after伪元素。例如：

* {
  margin: 0;
  padding: 0;
}
*, *:before, *:after {
    box-sizing: border-box;
}
section.wrap {
  display: flex;
  flex-flow: row wrap;
}
section.wrap:after {
  content: 'I am an inserted pseudo!';
  display: block;
  order: 1;
  width: 100%;
  background: yellow;
}

div {
  width: 33.33%;
  height: 40px;
  background-color: powderblue;
  border-top: solid 0px white;
  border-right: solid 5px white;
  border-bottom: solid 5px white;
  border-left: solid 0px white;
}

div:nth-of-type(3n + 3) {
    border-right: 0;
}

.inner {
    width: 100%;
    order: 2;
}

<section class="wrap">
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>
    <div class="float"></div>

    <!-- NO NEED TO CLEAR FLOATS, BUT WE CAN PUT A PSEUDO HERE -->

    <section class="inner">
        Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.
    </section>
</section>

- Ilya Streltsyn