Home Web Front-end CSS Tutorial What are the css selectors? Summary of css selector usage

What are the css selectors? Summary of css selector usage

Aug 18, 2018 pm 02:40 PM
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This article brings you what are the css selectors? A summary of the use of CSS selectors has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.

1. Selector (device) uses basic syntax
Selector { Attribute 1: Attribute value 1;
Attribute 2: Attribute value 2;
Attribute 3: Attribute value 3;
       …..: …….;
}
2. Tag selector (directly use HTML tags as selectors)
second.html

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<!doctype html>

<html>

<head>

    <meta charset="utf-8">

    <title>标记选择器</title>

    <link href="second.css" type="text/css"   rel="stylesheet">

</head>

<body>

    <p> 标记选择器(直接使用html标签做选择器)</p>

</body>

</html>

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second.css

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p{

    font-size:34px;  

    text-align:left;   

    text-transform:uppercase;   

    font-family:黑体,宋体;   

    text-indent:3em;   

    text-decoration:line-through;   

    font-weight:bolder;   

    letter-spacing:0.5em;   

    line-height:3px;   

    margin:34px;   

    padding:23px;

    }

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3. Class selector (for each The label sets a class name. CSS can set the style of the label through the class name. Different labels can have the same class name, and they can share the same style.) - In CSS, label name.class name or .class name is used to express

second.html

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<!doctype html>

<html>

<head>

    <meta charset="utf-8">

    <title>类选择器</title>

    <link href="second.css" type="text/css"   rel="stylesheet">

</head>

<body>

    <p  class="text"> 类选择器(为每一个标签设置一个类名,CSS可通过类名为标签设置样式,不同标签类名可以相同,

    相同可以共用同一个样式)---CSS中用标签名.类名或者.类名表示    </p>

</body>

</html>

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second.css

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.text{

    font-variant:small-caps;/*小型大写字母*/

    font-family:宋体,黑体;   

    font-style:italic;   

    text-transform:lowercase;   

    font-size:35px;   

    text-indent:3em;   

    text-decoration:overline;   

    font-weight:bold;   

    letter-spacing: 1px;   

    line-height:3em;   

    font-variant:small-caps;   

    text-align:right;

    }

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4.ID selector (set a unique ID for each HTML tag, CSS can set the style for the tag through the id)
——#id value { } is used in CSS to represent

second.html

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<!doctype html>

<html>

<head>

    <meta charset="utf-8">

    <title>ID选择器</title>

    <link href="second.css" type="text/css"   rel="stylesheet">

    </head>

    <body>

    <p  class="text" id="textp1"> ID选择器(为每一个HTML标签设置一个唯一的ID,CSS可以通过id来为标签设置样式)

    ----CSS中用#id值{ }来表示    </p>

    </body>

    </html>

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second.css

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.text{

    font-variant:small-caps;/*小型大写字母*/

    font-family:宋体,黑体;   

    font-style:italic;   

    text-transform:lowercase;   

    font-size:35px;   

    text-indent:3em;   

    text-decoration:overline;

    }

#textp1{

    font-weight:bold;   

    letter-spacing: 1px;   

    line-height:3em;   

    font-variant:small-caps;   

    text-align:right;

    }

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5. Contains selectors (descendant selectors: can span generation, cross tags): Contain another tag in one tag
second.html

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<!doctype html>

<html>

<head>

    <meta charset="utf-8">

    <title>包含选择器</title>

    <link href="second.css" type="text/css"   rel="stylesheet">

    </head>

    <body>

    <p  class="text" id="textp1">  <a href="#" class="link">ID选择器</a>

        (为每一个html标签设置一个唯一的ID,CSS可以通过id来为标签设置样式)

     ----CSS中用#id值{ }来表示    </p>

     </body>

     </html>

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second.css

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p a{

     

    text-decoration:none;   

    font-size:25px;   

    background-color:pink;

    }

.text{

    font-size:21px;   

    font-style:normal;   

    text-transform:lowercase;   

    text-indent:3em;   

    font-weight:bold;   

    letter-spacing:0.7em;   

    line-height:27px;

    }

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6. Sub-selector (not supported by IE browser): No other tags can be included in the middle; in CSS, tag 1 > tag 2 (sub-tag) is used to represent

second.html

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<!doctype html>

<html>

<head>

    <meta charset="utf-8">

    <title>子选择器</title>

    <link href="second.css" type="text/css"   rel="stylesheet">

    </head>

    <body>

    <p  class="text" id="textp1">

             <a href="#" class="link">子选择器</a>

            (IE浏览器不支持):中间不能包含其他标签;CSS中 标签1 >标签2(子标签) 表示

    </p>

    </body>

    </html>

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second.css

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p>a{

    text-decoration:none;   

    font-family:黑体,宋体;

    }

p{   

font-size: 23px;

}

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7. Adjacent Selector: (CSS style is applied to the last tag) Commonly used to set column attributes of the table – CSS uses tag 1….Tag n represents

second.html

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<!doctype html>

<html>

<head>

    <meta charset="utf-8">

    <title>相邻选择器</title>

    <link href="second.css" type="text/css"   rel="stylesheet">

    </head>

    <body>

    <p  class="text" >

            子选择器:

            (IE浏览器不支持):中间不能包含其他标签;CSS中 标签1 >标签2(子标签) 表示

    </p>

 

    <p class="text1">

        相邻选择器(CSS样式作用在最后一个标签)常用设置表格的列属性--CSS用标签1+....标签n表示    </p>

        </body>

        </html>

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second.css

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.text+.text1{

    color:pink;   

    background-color:gray;   

    font-size:34px;

    }

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8. Union selector: Set styles for multiple tags together, separated by commas

second.css

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<!doctype html>

<html>

<head>

    <meta charset="utf-8">

    <title>并集选择器</title>

    <link href="second.css" type="text/css"   rel="stylesheet">

    </head>

    <body>

    <p  class="text" >

            子选择器:

            (IE浏览器不支持):中间不能包含其他标签;CSS中 标签1 >标签2(子标签) 表示

    </p>

 

    <p class="text1">

        并集选择器:多个标签一起设置样式,用逗号隔开    </p>

        </body>

        </html>

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second.css

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.text,.text1{

    color:pink;

    background-color:gray;   

    font-size:34px;}

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9. Pseudo class (a certain state of an element, often used to describe the state of a hyperlink: link (unvisited state); visited (visited state); hover (mouse passing state); active (clicking state) CSS tags Name: Status representation

second.html

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<!doctype html>

<html>

<head>

    <meta charset="utf-8">

    <title>伪类</title>

    <link href="second.css" type="text/css"   rel="stylesheet">

    </head>

    <body>

    <a href="" class="a1">伪类</a>

    </body>

    </html>

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second.css

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a:link {

    color:blue;   

    font-size:53px;   

    text-decoration: none;

    }

a:visited {

    color:red;   

    font-size:193px;

    }

a:hover  {

    color:green;   

    font-size:73px;

    }

a:active  {

    color:gray;   

    font-size:183px;

    }

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10. Pseudo element (state of an element in an object) tag name in CSS : Pseudo-class representation
Commonly used ones are (first-letter [acts on the first letter of text], first-line [acts on the first line of text])
second.html

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<!doctype html>

<html>

<head>

    <meta charset="utf-8">

    <title>伪类</title>

    <link href="second.css" type="text/css"   rel="stylesheet">

    </head>

    <body>

    <p>伪元素(某个对象中某个元素的状态)CSS中用标签名:

 伪元素常用的有(first-letter[作用于文字首字],first-line[作用于文字首行]) 

 <br>伪元素(某个对象中某个元素的状态)CSS中用标签名:

 伪元素常用的有(first-letter[作用于文字首字],first-line[作用于文字首行])    </p>

 </body>

 </html>

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second.css

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p:first-letter{

    font-size:200%;

    }

p:first-line{

    color:red;

    }

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11 Style priority: Inline selector>ID selector>Class selector (pseudo-class, attribute)>Mark selector
You can use !important; to increase the priority
Related recommendations:

css class selector and id selector

##CSS descendant selector and multi-class selector

css tag selector, id selector, class selector instance

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