Web Front-end
HTML Tutorial
The priority of css introduction method and the priority difference of different selectors_html/css_WEB-ITnose
The priority of css introduction method and the priority difference of different selectors_html/css_WEB-ITnose
We all know that there are 3 basic settings for css, namely
1. Inline is also called embedded. For example:
<div style='background:red'></div>
2. Inline, wrapped with style tags in the html file. For example:
<html> <style type='text/css'> div{ background:red; } </style></html>
3. Link type, referenced using link tags in html files. For example:
<html> <link rel='stylesheet' type='text/css' href='style.css'/></html>
Note: There is another This @import writing method is not commonly used and has compatibility issues. It is ignored.
When we use these three methods at the same time to set styles on the same target element, the priority is inline > inline > link
Generally, in the same way (file), whoever comes next has the highest priority. Many people know this,
But many people ignore that different selectors also have priorities.
First of all, let’s recall the css selector type
#id name{ attribute name: attribute value; }
.class name{ attribute name: attribute value; }
tag name{ attribute name: attribute value; }
This is one of the 3 basic selectors. There are compound selectors that combine them with each other
We write a css style file and introduce it into the css.html
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title>css优先级讨论</title></head><link rel="stylesheet" type="text/css" href="base.css"/><body> <div id='red' class='blue' >颜色</div></body></html>
base.css file As follows
@charset "utf-8";/* CSS Document */#red{ color:red;}.blue{ color:blue;}div{ color:black;}
These three style settings are all for one element and are all in the link file. They should override the previous ones in order, but the browser The result of the operation is
This means that the id selector has the highest priority. Please see the figure below for the specific selector weight
Through this picture, we can calculate which setting has a higher priority. At the same time, we will also realize that the priority of the link may be greater than the embedded one! In practice, we often encounter this kind of error caused by problems. Now let’s look at a practical example
In this page, the color attribute of the button "Next" is set three times, and all of them are In the base.css file, the subsequent color values do not overwrite the previous settings and become white, because the first circle uses a class label weight of 11, the second circle uses a class weight of 10, and the last one uses a label weight of 1. Naturally, the effective solution for the first setting is very simple. Change the second selector and the result is as follows
The weight values are equal and the back covers the front. That’s it. It’s not enough for errors. Please point it out.
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
AI Hentai Generator
Generate AI Hentai for free.
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
Difficulty in updating caching of official account web pages: How to avoid the old cache affecting the user experience after version update?
Mar 04, 2025 pm 12:32 PM
The official account web page update cache, this thing is simple and simple, and it is complicated enough to drink a pot of it. You worked hard to update the official account article, but the user still opened the old version. Who can bear the taste? In this article, let’s take a look at the twists and turns behind this and how to solve this problem gracefully. After reading it, you can easily deal with various caching problems, allowing your users to always experience the freshest content. Let’s talk about the basics first. To put it bluntly, in order to improve access speed, the browser or server stores some static resources (such as pictures, CSS, JS) or page content. Next time you access it, you can directly retrieve it from the cache without having to download it again, and it is naturally fast. But this thing is also a double-edged sword. The new version is online,
How do I use HTML5 form validation attributes to validate user input?
Mar 17, 2025 pm 12:27 PM
The article discusses using HTML5 form validation attributes like required, pattern, min, max, and length limits to validate user input directly in the browser.
How to efficiently add stroke effects to PNG images on web pages?
Mar 04, 2025 pm 02:39 PM
This article demonstrates efficient PNG border addition to webpages using CSS. It argues that CSS offers superior performance compared to JavaScript or libraries, detailing how to adjust border width, style, and color for subtle or prominent effect
What are the best practices for cross-browser compatibility in HTML5?
Mar 17, 2025 pm 12:20 PM
Article discusses best practices for ensuring HTML5 cross-browser compatibility, focusing on feature detection, progressive enhancement, and testing methods.
What is the purpose of the <datalist> element?
Mar 21, 2025 pm 12:33 PM
The article discusses the HTML <datalist> element, which enhances forms by providing autocomplete suggestions, improving user experience and reducing errors.Character count: 159
What is the purpose of the <meter> element?
Mar 21, 2025 pm 12:35 PM
The article discusses the HTML <meter> element, used for displaying scalar or fractional values within a range, and its common applications in web development. It differentiates <meter> from <progress> and ex
How do I use the HTML5 <time> element to represent dates and times semantically?
Mar 12, 2025 pm 04:05 PM
This article explains the HTML5 <time> element for semantic date/time representation. It emphasizes the importance of the datetime attribute for machine readability (ISO 8601 format) alongside human-readable text, boosting accessibilit
What is the purpose of the <progress> element?
Mar 21, 2025 pm 12:34 PM
The article discusses the HTML <progress> element, its purpose, styling, and differences from the <meter> element. The main focus is on using <progress> for task completion and <meter> for stati
