How to clear floating pseudo elements

How to clear floating pseudo elements and sample code

Introduction:

In front-end development, float (float) is a commonly used layout method . However, floating elements may cause the height of the parent element to collapse, causing layout confusion. To avoid this problem, we can use pseudo elements to clear floats.

What is a pseudo element?

Pseudo elements are a new element in CSS3 that can add styles to an element in the document without actually adding additional elements to HTML.

There are two main forms of pseudo elements:

1. ::before: Insert a pseudo element before the element content, which can be used to add style or content.
2. ::after: Insert a pseudo element after the element content, which can also be used to add style or content.

How to use pseudo elements to clear floats?

In the process of using pseudo elements to clear floats, we need to use the content attribute of CSS to define the content of the pseudo element as empty, and then set the display attribute on the pseudo element to table, table-row or table- cell to trigger BFC (block-level formatting context).

The following is some sample code:

<style>
  .clearfix::after {
    content: "";
    display: table;
    clear: both;
  }

  .float-left {
    float: left;
  }

  .float-right {
    float: right;
  }
</style>

<div class="clearfix">
  <div class="float-left">左浮动元素</div>
  <div class="float-right">右浮动元素</div>
</div>

In the above sample code, we created a clearfix class, and then set the content to an empty string in its ::after pseudo-element, The display attribute is table and the clear attribute is both. In the HTML structure, we used left-floated and right-floated elements and then wrapped them in a clearfix container.

In this way, a pseudo element without actual content is added after the clearfix container. Since the display attribute of the pseudo element is table, BFC will be triggered, thus creating a new block-level formatting context. This clears the float and avoids container height collapse issues.

Note:

1. The method of clearing floats is not limited to using pseudo elements, but can also use other methods, such as using the overflow attribute, empty tags, etc.
2. When using pseudo elements to clear floats, you need to pay attention to browser compatibility. Different browsers have different levels of support for pseudo-elements. You can use CSS Hack or CSS preprocessors to solve compatibility issues.

Summary:

By using pseudo elements to clear floats, we can avoid the height collapse problem of parent elements caused by floating elements and ensure the maintainability and readability of the code. In actual development, different floating methods can be selected according to specific circumstances in order to achieve the best effect.

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