12 Tips for CSS Code Optimization_Experience Exchange
1.ID Rules
2.Class Rules
3. Tag Rules
4. General Rules
The common understanding of efficiency comes from "High-Performance Website Construction" published by Steve Souders in 2009 Starting with "Advanced Guide", although the book lists it in more detail, you can also view the complete reference list here, or you can view more details in Google's "Best Practices for Efficient CSS Selectors".
In this article I want to share some simple examples and guidelines that I use to write high-performance CSS. These are inspired by the guide to efficient CSS written by MDN and follow a similar format.
1. Avoid excessive restraint
As a general rule, don't add unnecessary constraints.
// Oops
ul#someid {. .}
.menu#otherid{..}
// OK
#someid {..}
#otherid {..}
2. The descendant selector is the worst
Not only is the performance low, but the code is also very fragile. The html code and the css code are severely coupled. When the html code structure changes, the CSS must also be modified. , how bad this is, especially in large companies, the people who write HTML and CSS are often not the same people.
// It sucks
html div tr td {..}
3. Avoid chain (intersection) selectors
This is similar to the over-constraint situation. A more sensible approach is to simply create a new CSS class selector.
// Oops
.menu.left. icon {..}
// OK
.menu-left-icon {..}
4. Adhere to the KISS principle
Imagine we have the following DOM:
The following are the corresponding rules...
/ / Bad
#navigator li a {..}
// Good
#navigator {..}
5. Use compound (compact) syntax
Use compound syntax as much as possible.
// Oops
.someclass {
padding-top: 20px;
padding-bottom: 20px;
padding-left: 10px;
padding-right: 10px;
background: #000;
background-image: url (../imgs/carrot.png);
background-position: bottom;
background-repeat: repeat-x;
}
// Okay
.someclass {
padding: 20px 10px 20px 10px;
background: #000 url(../imgs/carrot.png) repeat-x bottom;
}
6. Avoid unnecessary namespaces
// Bad
.someclass table tr.otherclass td.somerule {..}
//Good
.someclass .otherclass td.somerule { ..}
7. Avoid unnecessary repetition
Combine repeated rules as much as possible.
// Oops
.someclass {
color: red;
background: blue;
font-size: 15px;
}
.otherclass {
color: red;
background: blue ;
font-size: 15px;
}
// OK
.someclass, .otherclass {
color: red;
background: blue;
font-size: 15px;
}
8. Streamline the rules as much as possible
Based on the above rules, you can further merge Repeated rules in different categories.
// Oops
.someclass {
color: red;
background: blue;
height: 150px;
width : 150px;
font-size: 16px;
}
.otherclass {
color: red;
background: blue;
height: 150px;
width : 150px;
font-size: 8px;
}
// OK
.someclass, .otherclass {
color: red;
background: blue; height: 150px;
width: 150px;
}
.someclass {
font-size: 16px;
}
.otherclass {
font-size: 8px;
}
9. Avoid unclear naming conventions
It is best to use names that express semantics. A good CSS class name should describe what it is rather than what it looks like.
10. Avoid !importants
In fact, you should also be able to use other high-quality selectors.
11. Follow a standard declaration order
While there are some common ways to order CSS properties, below is a popular way that I follow.
.someclass {
/* Positioning */
/* Display & Box Model */
/* Background and typography styles */
/* Transitions */
/* Other */
}
12. Organized code format
The readability of the code is directly proportional to the ease of maintainability. Below is the formatting method I follow.
// Oops
.someclass-a, .someclass-b, .someclass-c, .someclass-d {
...
}
// Okay
.someclass-a,
.someclass-b ,
.someclass-c,
.someclass-d {
...
}
// Good practice
.someclass {
background-image :
linear-gradient(#000, #ccc),
linear-gradient(#ccc, #ddd); 1px 1px #ddd inset;
}
Obviously, these are just a few of the rules that I try to follow in my own CSS in order to be more efficient and maintainable. If you want to read more, I recommend reading MDN’s Guide to Writing Efficient CSS and Google’s Guide to Optimizing Browser Rendering.

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

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

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



Using Bootstrap in Vue.js is divided into five steps: Install Bootstrap. Import Bootstrap in main.js. Use the Bootstrap component directly in the template. Optional: Custom style. Optional: Use plug-ins.

HTML defines the web structure, CSS is responsible for style and layout, and JavaScript gives dynamic interaction. The three perform their duties in web development and jointly build a colorful website.

There are two ways to create a Bootstrap split line: using the tag, which creates a horizontal split line. Use the CSS border property to create custom style split lines.

WebdevelopmentreliesonHTML,CSS,andJavaScript:1)HTMLstructurescontent,2)CSSstylesit,and3)JavaScriptaddsinteractivity,formingthebasisofmodernwebexperiences.

To adjust the size of elements in Bootstrap, you can use the dimension class, which includes: adjusting width: .col-, .w-, .mw-adjust height: .h-, .min-h-, .max-h-

How to use the Bootstrap button? Introduce Bootstrap CSS to create button elements and add Bootstrap button class to add button text

To set up the Bootstrap framework, you need to follow these steps: 1. Reference the Bootstrap file via CDN; 2. Download and host the file on your own server; 3. Include the Bootstrap file in HTML; 4. Compile Sass/Less as needed; 5. Import a custom file (optional). Once setup is complete, you can use Bootstrap's grid systems, components, and styles to create responsive websites and applications.

There are several ways to insert images in Bootstrap: insert images directly, using the HTML img tag. With the Bootstrap image component, you can provide responsive images and more styles. Set the image size, use the img-fluid class to make the image adaptable. Set the border, using the img-bordered class. Set the rounded corners and use the img-rounded class. Set the shadow, use the shadow class. Resize and position the image, using CSS style. Using the background image, use the background-image CSS property.
