CSS specification of web front end

JavaScript language 2020-11-13 05:03:58
css specification web end


CSS Refers to cascading style sheets (Cascading Style Sheets), Define how to display HTML Elements , But because of CSS Born global , As project complexity increases , It is easy to have style coverage and other problems .

1. General specifications

File encoding

  • In order to avoid the content garbled , Unified use UTF-8 Encoding preservation .

  • The first line of the style file sets the character set to UTF-8

@charset 'UTF-8'; /* Note that the character set description should be on the first line */

Indent specification

Unified use Two spaces indented

2. Initialization specification

The initial style of each browser manufacturer is different , In order to eliminate different browsers from HTML Differences in text presentation , We often introduce some initialization styles , Such as normalize.css、reset.css etc. , When introducing these styles, we need to pay attention to the following situations :

  • Don't use UI frame , Build from scratch
    In the case of building from scratch , To initialize the style , Introduce... At the beginning of the project , Don't introduce... In the middle of development , Avoid unpredictable style conflicts .

  • Don't use UI frame , But some plug-ins are used
    Plug ins often have their own style , Such as rich text plug-ins , Using initialization styles in the middle of development can lead to style confusion , Therefore, extensive initialization is not recommended , just Simply initialize that will do .

* {
padding: 0;
margin: 0;
}
  • Already used UI frame
    When you know clearly that you need to use UI Frame time , Do not use third-party initialization styles , Whether before or during the project , because UI Frameworks usually come with initialization , The addition will affect the original effect .

3. Code specification

Naming specification

class Should be named after function or content , It's not named in terms of expression
class And id The letters of words are lower case , When multiple words are formed , Use the center line - Separate
Use the only id As Javascript hook, At the same time, avoid creating no style information class
web Front end development resources Q-q-u-n: 767273102 , There are free development tools , Zero basis , Advanced video tutorial , I hope novices don't take detours

Code style.

  • Unified use Expand the format , Compact format is not recommended

    /* Expand the format */
    .test {
    color: red;
    font-size: 12px;
    }
    
    /* Compact format */
    .test {
    color: red;
    font-size: 12px;
    }
    
  • Unified Two spaces Indent

  • A semicolon is added at the end of the property declaration

  • A space between the selector and the left bracket , The space after the property colon

    /* recommend */
    .test {
    color: red;
    font-size: 12px;
    }
    
    /* Not recommended */
    .test {
    color: red;
    font-size: 12px;
    }
    
  • Don't do it 0 Designated unit

  • Color value and attribute value hexadecimal value can be abbreviated as much as possible

    /* recommend */
    .test {
    color: #fff;
    }
    
    /* Not recommended */
    .test {
    color: #ffffff;
    }
    
  • Use quotation marks

    url() 、 Property selector 、 Attribute value usage Single quotation marks .

  • Remove the floating

    When an element needs to be raised to include an internal floating element , By setting the pseudo class clear Or trigger BFC By clearfix. Try not to add empty tags .

    Trigger BFC There are many ways , Common are :

    • float Not none
    • position Not static
    • overflow Not visible

Font specifications

  • Foreign business website , Do not use font-face introduce Microsoft YaHei typeface , Avoid infringement ( Including picture content )
  • Need to be in Windows Chinese content displayed on the platform , Its font size should not be less than 12px
 Use on website Microsoft YaHei There are three forms of typeface :
1、【 tort 】 Use... In the picture Microsoft YaHei typeface , For example, the website header map
2、【 Security 】 Website CSS use font-family Declare that the site uses Microsoft YaHei typeface , For example, the title and body of the article
3、【 tort 】 Website through font-face quote Microsoft YaHei , It's not common

Selector specifications

In strict compliance with BEM(Block Element Modifier) when , Only class selectors are recommended , but BEM Writing trouble , So the suggestions are as follows

  • Disable universal selector *
  • Do not use tag selectors without specific semantic definitions

Attribute order

CSS The attributes are in order CSS Part of a good coding style , Helps improve code readability , Easy to find code problems , It's good for teamwork , But in the project found that some students in the writing attribute order is more casual , Think of an attribute and write a .

It is recommended to write in the following order

  1. Location attribute (position、display、float、left、right)
  2. Dimension properties (width、height、padding、margin、border)
  3. Font properties (color、font、text-align)
  4. Other attributes (background、cursor、outline)

The goal is to browse code , Can gradually clear the effect of the target element .

.test {
display: block;
position: relative;
float: left;
width: 100px;
height: 100px;
margin: 0 10px;
padding: 20px 0;
font-size: 12px;
color: #333;
background: rgba(0, 0, 0, 0.5);
border-radius: 10px;
}
web Front end development resources Q-q-u-n: 767273102 , There are free development tools , Zero basis , Advanced video tutorial , I hope novices don't take detours

4. Annotation specifications

Single-line comments

Annotate with /* Start , With */ end , Comments cannot be nested within comments , The comment Leave a space before and after .

/* Recommended single line comments */
/* One line comment not recommended */

notes : stay sass and less Double slash annotations can also be used in preprocessing languages , But after compiling, the comments will not appear in css In file , Therefore, it is recommended to use /* */ notes .

Module annotation

Sometimes we need a module ( A block of code ) Make a functional statement , And can clearly distinguish other codes , We can use module annotations .

Annotate with /* Start , With */ end , Leave a space before and after , Fill in the first line describe , Fill in the last line Split line .

/* Recommended module comments
---------------------------------------------------- */
/* Module comments not recommended ---------------------------------------------------- */

* File information notes

If a functional document is needed , Make it easy for others to quickly understand the purpose of this document , Recommended at the beginning of the file ( Under the character set description ) Write the following comments , The comments include a description of the document 、 founder 、 Creation time, etc .

@charset "UTF-8";
/**
* @desc File function description , Make it easy for others to quickly understand
* @author founder
* @date Creation time
*/

5. Covering specifications

  • As far as possible To use less importent
  • vue Unified use of single file components css/less/sass scoped
  • Every page / The component needs to have a Globally unique The logo of id/class, All the styles under it need to be marked with the unique identification
  • Avoid global modification of existing styles , It has to be specific to the page ( By weight )
  • Disable full matching * Selectors ( Except in special cases , Such as initialization )

vue Single file component modification style does not take effect. You can use /deep/ or >>>

6. Media query

For the internal management system , Business uses more ThinkPad The notebook , The screen resolution is 1366*768. It is recommended to use Resolution Test Browser development for browser window size debugging .

Download address :www.cnplugins.com/devtool/res…

The common sizes are as follows

size describe
≥1366px A big screen Large desktop display
≥1200px Medium screen Desktop display
≥992px Medium screen Desktop display
≥768px A small screen Flat
<768px Super small screen mobile phone

first PC End

By default, the layout is based on the maximum size , As the size shrinks, it gradually becomes the mobile terminal layout

body {
background: gray;
}
@media screen and (max-width: 1366px) {
body {
background: red;
}
}
@media screen and (max-width: 1200px) {
body {
background: yellow;
}
}
@media screen and (max-width: 920px) {
body {
background: green;
}
}
@media screen and (max-width: 768px) {
body {
background: black;
}
}

Priority mobile end

By default, the layout is based on the minimum size , As the size increases, it gradually becomes PC End layout

body {
background: gray;
}
@media (min-width: 768px) {
body {
background: red;
}
}
@media (min-width: 920px) {
body {
background: green;
}
}
@media (min-width: 1200px) {
body {
background: yellow;
}
}
@media (min-width: 1366px) {
body {
background: red;
}
}

If you need to make a print style to fit , Need to use @media print

@media print {
body {
background: #fff;
}
}
web Front end development resources Q-q-u-n: 767273102 , There are free development tools , Zero basis , Advanced video tutorial , I hope novices don't take detours

7. Unit specifications

CSS There are two kinds of units , Namely Absolute units and Relative units .

  • Absolute units are often used

    • px: Pixels ( A dot on a computer screen )
    • cm: centimeter
    • in: Inch
    • pt: pounds (1 pt be equal to 1/72 Inch )
  • A common relative unit

    • %: Percentage of parent element
    • vw: Percentage of the width of the viewport
    • vh: Percentage of view height
    • em: Current font multiple
    • rem: Root element font multiple
    • * rpx: Wechat applet dedicated , Set the screen width to 750rpx

The more used units are px、%、rem Three , Suggest PC End use px Company 、 Mobile terminal rem, Need to control the size or use px

remarks : If you need to calculate values in different units , have access to css3 Method calc()_

8. Compatibility Specification

The use of private properties

It is because of the different browser manufacturers , As a result, some styles need to be prefixed to work , The following common browser kernels and prefixes

browser kernel Prefix
Firefox Gecko -moz-
Chrome WebKit -webkit-
IE Trident -ms-
Safari WebKit -webkit-
Opera Presto -o-
Domestic famous browser WebKit -webkit-
Common mobile browsers WebKit -webkit-

CSS3 Browser private prefix before , The standard prefix follows

.test {
-webkit-border-radius: 10px;
-moz-border-radius: 10px;
-o-border-radius: 10px;
-ms-border-radius: 10px;
border-radius: 10px;
}

remarks : stay webpack In the environment , have access to postcss-loader Auto add private prefix _

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