如何从伪元素内容中插入HTML标记：[复制](How to inserted HTML tag from pseudo-element content: [duplicate])

 您不能使用CSS伪元素的content属性注入HTML元素; 但是，您可以将它们设置为display: block和（在您的问题中似乎需要，但不是您演示/尝试过的代码）使用height和background-color来模拟<hr /> ： 
 
article::before {
    content: '';
    display: block;
    margin: 1em 0;
    height: 5px;
    background-color: #f00;
}
 
 
 
 
 
  
article::before {
  content: '';
  display: block;
  margin: 1em 0;
  height: 5px;
  background-color: #f00;
}
 
  
<article>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</article>
<article>Contrary to popular belief, Lorem Ipsum is not simply random text. It has roots in a piece of classical Latin literature from 45 BC, making it over 2000 years old. Richard McClintock, a Latin professor at Hampden-Sydney College in Virginia, looked up one of the more obscure Latin words, consectetur, from a Lorem Ipsum passage, and going through the cites of the word in classical literature, discovered the undoubtable source. Lorem Ipsum comes from sections 1.10.32 and 1.10.33 of "de Finibus Bonorum et Malorum" (The Extremes of Good and Evil) by Cicero, written in 45 BC. This book is a treatise on the theory of ethics, very popular during the Renaissance. The first line of Lorem Ipsum, "Lorem ipsum dolor sit amet..", comes from a line in section 1.10.32.</article>
 
 
 
 
 
 当然，你可以提供一个width ，并使用auto作为margin-left和margin-right来居中一个'较短'的伪<hr /> ： 
 
article::before {
    content: '';
    display: block;
    margin: 1em auto;
    height: 5px;
    width: 80%;
    background-color: #f00;
}
 
 
 
 
 
  
article::before {
  content: '';
  display: block;
  margin: 1em auto;
  height: 5px;
  width: 80%;
  background-color: #f00;
}
 
  
<article>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has
  survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing
  software like Aldus PageMaker including versions of Lorem Ipsum.</article>
<article>Contrary to popular belief, Lorem Ipsum is not simply random text. It has roots in a piece of classical Latin literature from 45 BC, making it over 2000 years old. Richard McClintock, a Latin professor at Hampden-Sydney College in Virginia, looked up
  one of the more obscure Latin words, consectetur, from a Lorem Ipsum passage, and going through the cites of the word in classical literature, discovered the undoubtable source. Lorem Ipsum comes from sections 1.10.32 and 1.10.33 of "de Finibus Bonorum
  et Malorum" (The Extremes of Good and Evil) by Cicero, written in 45 BC. This book is a treatise on the theory of ethics, very popular during the Renaissance. The first line of Lorem Ipsum, "Lorem ipsum dolor sit amet..", comes from a line in section
  1.10.32.</article>
 
 
 
 
 
 如果您不想在第一个<article>之前使用此伪<hr /> ，则可以将选择器更改为： 
 
article:not(:first-child)::before { /* ...CSS... */}
 
 或者，假设<article>元素是兄弟姐妹： 
 
article + article::before { /* ...CSS... */ }

You can't inject HTML elements using the content property of CSS pseudo-elements; you can, however, set them to display: block and (as seems to be required in your question, though not your demonstrated/attempted code) use height and background-color to emulate an <hr />:
 
article::before {
    content: '';
    display: block;
    margin: 1em 0;
    height: 5px;
    background-color: #f00;
}
 
 
 
 
 
  
article::before {
  content: '';
  display: block;
  margin: 1em 0;
  height: 5px;
  background-color: #f00;
}
 
  
<article>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</article>
<article>Contrary to popular belief, Lorem Ipsum is not simply random text. It has roots in a piece of classical Latin literature from 45 BC, making it over 2000 years old. Richard McClintock, a Latin professor at Hampden-Sydney College in Virginia, looked up one of the more obscure Latin words, consectetur, from a Lorem Ipsum passage, and going through the cites of the word in classical literature, discovered the undoubtable source. Lorem Ipsum comes from sections 1.10.32 and 1.10.33 of "de Finibus Bonorum et Malorum" (The Extremes of Good and Evil) by Cicero, written in 45 BC. This book is a treatise on the theory of ethics, very popular during the Renaissance. The first line of Lorem Ipsum, "Lorem ipsum dolor sit amet..", comes from a line in section 1.10.32.</article>
 
 
 
 
 
You could, of course, supply a width, and use auto for margin-left and margin-right to centre a 'shorter' pseudo-<hr />:
 
article::before {
    content: '';
    display: block;
    margin: 1em auto;
    height: 5px;
    width: 80%;
    background-color: #f00;
}
 
 
 
 
 
  
article::before {
  content: '';
  display: block;
  margin: 1em auto;
  height: 5px;
  width: 80%;
  background-color: #f00;
}
 
  
<article>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has
  survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing
  software like Aldus PageMaker including versions of Lorem Ipsum.</article>
<article>Contrary to popular belief, Lorem Ipsum is not simply random text. It has roots in a piece of classical Latin literature from 45 BC, making it over 2000 years old. Richard McClintock, a Latin professor at Hampden-Sydney College in Virginia, looked up
  one of the more obscure Latin words, consectetur, from a Lorem Ipsum passage, and going through the cites of the word in classical literature, discovered the undoubtable source. Lorem Ipsum comes from sections 1.10.32 and 1.10.33 of "de Finibus Bonorum
  et Malorum" (The Extremes of Good and Evil) by Cicero, written in 45 BC. This book is a treatise on the theory of ethics, very popular during the Renaissance. The first line of Lorem Ipsum, "Lorem ipsum dolor sit amet..", comes from a line in section
  1.10.32.</article>
 
 
 
 
 
If you don't want this pseudo-<hr /> before the first <article> you could change your selector to:
 
article:not(:first-child)::before { /* ...CSS... */}
 
Or, assuming the <article> elements are siblings:
 
article + article::before { /* ...CSS... */ }