亚洲国产日韩欧美一区二区三区,精品亚洲国产成人av在线,国产99视频精品免视看7,99国产精品久久久久久久成人热,欧美日韩亚洲国产综合乱

Table of Contents
Basic usage: Add simple text or style
Layout and decoration: Small details that enhance visual effects
Clear floating or other auxiliary functions
Notes and FAQs
Home Web Front-end CSS Tutorial Employing CSS pseudo-elements (`::before`, `::after`)

Employing CSS pseudo-elements (`::before`, `::after`)

Jul 06, 2025 am 12:05 AM

<p>Use CSS pseudo-elements (::before and ::after) to insert content and enhance visual effects without modifying HTML. 1. The basic usage is to add text or symbols through the content attribute, such as inserting red prompt text before the paragraph; 2. Common techniques include inserting quotes, arrows, icon fonts, and implementing small triangles and other UI details; 3. You can use to match positioning and styles to achieve decorative effects, such as small triangles in the prompt box, button hovering effect, etc.; 4. It was used to clear floats, such as .clearfix::after to solve the floating collapse problem; 5. Notes include: content must exist, pseudo-elements default to inline, cannot be operated by JS, and are not suitable for placing important content because it affects accessibility and SEO. Rational use of pseudo-elements can simplify structure and enhance expressiveness, but abuse of key information should be avoided.

<p>Employing CSS pseudo-elements (`::before`, `::after`)

<p> Using CSS pseudo-elements ( ::before and ::after ) allows us to insert additional content before and after elements in the page without modifying the HTML structure. This is very practical when doing scenes such as decorative content, icons, prompt information, etc.

Employing CSS pseudo-elements (`::before`, `::after`)

Basic usage: Add simple text or style

<p> The most basic purpose is to insert text or symbols through content attribute. for example:

Employing CSS pseudo-elements (`::before`, `::after`)
 p::before {
  content: "Note:";
  color: red;
}
<p> This will prepend each <p> tag with the red "Note:". It should be noted that if content is not set or the value is an empty value other than the empty string, the pseudo-element will not be displayed .

<p> Common tips include:

Employing CSS pseudo-elements (`::before`, `::after`)
  • Insert quotation marks, arrows, icon fonts
  • Add a decorative line or background decoration
  • Implement UI details such as small triangles and dots

Layout and decoration: Small details that enhance visual effects

<p> Pseudo-elements are not only used to add text, but can also be used in conjunction with positioning and style to achieve some small visual decoration. For example, the common "prompt box with arrows" can be used to draw small triangles using ::after :

 .tooltip::after {
  content: "";
  position: absolute;
  bottom: -10px;
  left: 50%;
  transform: translateX(-50%);
  border-width: 10px 10px 0;
  border-style: solid;
  border-color: #333 transparent transparent transparent;
}
<p> The advantage of this practice is that it does not require additional labels and is clean in structure. Similar things include button hover effect, gradient border, shadow enhancement, etc., which can all be achieved with the help of pseudo-elements.

Clear floating or other auxiliary functions

<p> Although Flexbox and Grid are now widely used, in some old projects ::after is also commonly used to clear floats. for example:

 .clearfix::after {
  content: "";
  display: table;
  clear: both;
}
<p> This method can solve the floating collapse problem without removing HTML elements. While modern layouts have reduced this need, knowing it can still help maintain old code.

Notes and FAQs

<p> Pay attention to the following points when using pseudo-elements to avoid getting stuck:

  • content must be available, even if it is just an empty string ""
  • The pseudo-element is inline by default, and display needs to be adjusted according to the situation.
  • You can set width, height, positioning, animation and other styles, but they cannot be retrieved or operated by JS.
  • Not suitable for important content because they are not in the DOM and are not accessible and SEO friendly
<p> In addition, the content of the pseudo-element will not be selected by the user, nor will it be indexed by the search engine as the main content, so it is only suitable for display additional content.

<p> Basically that's it. If pseudo-elements are used well, they can simplify the structure and improve expressiveness, but don't abuse them, especially not to insert key information.

The above is the detailed content of Employing CSS pseudo-elements (`::before`, `::after`). For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undress AI Tool

Undress AI Tool

Undress images for free

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

CSS tutorial for creating loading spinners and animations CSS tutorial for creating loading spinners and animations Jul 07, 2025 am 12:07 AM

There are three ways to create a CSS loading rotator: 1. Use the basic rotator of borders to achieve simple animation through HTML and CSS; 2. Use a custom rotator of multiple points to achieve the jump effect through different delay times; 3. Add a rotator in the button and switch classes through JavaScript to display the loading status. Each approach emphasizes the importance of design details such as color, size, accessibility and performance optimization to enhance the user experience.

Addressing CSS Browser Compatibility issues and prefixes Addressing CSS Browser Compatibility issues and prefixes Jul 07, 2025 am 01:44 AM

To deal with CSS browser compatibility and prefix issues, you need to understand the differences in browser support and use vendor prefixes reasonably. 1. Understand common problems such as Flexbox and Grid support, position:sticky invalid, and animation performance is different; 2. Check CanIuse confirmation feature support status; 3. Correctly use -webkit-, -moz-, -ms-, -o- and other manufacturer prefixes; 4. It is recommended to use Autoprefixer to automatically add prefixes; 5. Install PostCSS and configure browserslist to specify the target browser; 6. Automatically handle compatibility during construction; 7. Modernizr detection features can be used for old projects; 8. No need to pursue consistency of all browsers,

Styling visited links differently with CSS Styling visited links differently with CSS Jul 11, 2025 am 03:26 AM

Setting the style of links you have visited can improve the user experience, especially in content-intensive websites to help users navigate better. 1. Use CSS's: visited pseudo-class to define the style of the visited link, such as color changes; 2. Note that the browser only allows modification of some attributes due to privacy restrictions; 3. The color selection should be coordinated with the overall style to avoid abruptness; 4. The mobile terminal may not display this effect, and it is recommended to combine it with other visual prompts such as icon auxiliary logos.

Creating custom shapes with css clip-path Creating custom shapes with css clip-path Jul 09, 2025 am 01:29 AM

Use the clip-path attribute of CSS to crop elements into custom shapes, such as triangles, circular notches, polygons, etc., without relying on pictures or SVGs. Its advantages include: 1. Supports a variety of basic shapes such as circle, ellipse, polygon, etc.; 2. Responsive adjustment and adaptable to mobile terminals; 3. Easy to animation, and can be combined with hover or JavaScript to achieve dynamic effects; 4. It does not affect the layout flow, and only crops the display area. Common usages are such as circular clip-path:circle (50pxatcenter) and triangle clip-path:polygon (50%0%, 100 0%, 0 0%). Notice

What is the difference between display: inline, display: block, and display: inline-block? What is the difference between display: inline, display: block, and display: inline-block? Jul 11, 2025 am 03:25 AM

Themaindifferencesbetweendisplay:inline,block,andinline-blockinHTML/CSSarelayoutbehavior,spaceusage,andstylingcontrol.1.Inlineelementsflowwithtext,don’tstartonnewlines,ignorewidth/height,andonlyapplyhorizontalpadding/margins—idealforinlinetextstyling

How to create responsive images using CSS? How to create responsive images using CSS? Jul 15, 2025 am 01:10 AM

To create responsive images using CSS, it can be mainly achieved through the following methods: 1. Use max-width:100% and height:auto to allow the image to adapt to the container width while maintaining the proportion; 2. Use HTML's srcset and sizes attributes to intelligently load the image sources adapted to different screens; 3. Use object-fit and object-position to control image cropping and focus display. Together, these methods ensure that the images are presented clearly and beautifully on different devices.

What is CSS and what does it stand for? What is CSS and what does it stand for? Jul 03, 2025 am 01:48 AM

CSS,orCascadingStyleSheets,isthepartofwebdevelopmentthatcontrolsawebpage’svisualappearance,includingcolors,fonts,spacing,andlayout.Theterm“cascading”referstohowstylesareprioritized;forexample,inlinestylesoverrideexternalstyles,andspecificselectorslik

What is the CSS Painting API? What is the CSS Painting API? Jul 04, 2025 am 02:16 AM

TheCSSPaintingAPIenablesdynamicimagegenerationinCSSusingJavaScript.1.DeveloperscreateaPaintWorkletclasswithapaint()method.2.TheyregisteritviaregisterPaint().3.ThecustompaintfunctionisthenusedinCSSpropertieslikebackground-image.Thisallowsfordynamicvis

See all articles