CSS的选择器

作者: 阿凡提说AI | 来源:发表于2017-07-16 08:33 被阅读4次

    1.标签选择器、类选择器、id选择器、后代选择器

    <!DOCTYPE html>
    <html>
    <head lang="en">
        <meta charset="UTF-8">
        <title></title>
        <style>
            /*标签选择器*/
            div{
                color: red;
            }
    
            p{
                color: blue;
            }
            /*类选择器*/
            .one{
                color: yellow;
            }
            /*id选择器*/
            #main{
                font-size: 40px;
            }
            /*后代选择器*/
            #test2 div{
                color: green;
            }
        </style>
    </head>
    <body>
       <div id="main">1111111111</div>
       <div>1111111111</div>
       <div>1111111111</div>
       <p>2222222222222</p>
    
       <div class="one">222222</div>
       <p class="one">444444444</p>
       <div id="test2">
           <p>
               <div class="test1">
                  rewgrgrtwgrt
               </div>
           </p>
       </div>
    </body>
    </html>
    

    2.伪类

    <!DOCTYPE html>
    <html>
    <head lang="en">
        <meta charset="UTF-8">
        <title></title>
        <style>
            div{
                background-color: red;
                width: 200px;
                height: 300px;
            }
    
            div:hover{
                background-color: green;
                width: 100px;
                height: 180px;
            }
    
            input:focus{
                outline: none;
                width: 500px;
                height: 300px;
                border: 10px double yellow;
            }
        </style>
    </head>
    <body>
       <div>11111</div>
       <p></p>
       <input>
    </body>
    </html>
    

    3.选择器的优先级别

    <!DOCTYPE html>
    <html>
    <head lang="en">
        <meta charset="UTF-8">
        <title></title>
    
        <!--
         css选择器遵循:
         1.在相同级别:1.叠加原则  2.就近原则
         2. id选择器> 类选择器 > 标签选择器
         3. 范围越小,优先级别越高
        -->
        <style>
    
            div#main{  /*101*/
               color: goldenrod;
            }
    
            /*id选择器*/
            #main{  /*100*/
                color: deeppink;
            }
    
            /*类选择器*/
            .test2{   /*10*/
                color: purple;
            }
    
            .test1{   /*10*/
                color: yellow;
            }
    
            /*标签选择器*/
            div{   /*1*/
                color: red;
            }
            div{  /*1*/
                color: green;
            }
            div{   /*1*/
                color: blue;
                font-size: 100px;
            }
    
            *{  /*1000*/
                color: darkgreen  !important;
            }
        </style>
    </head>
    <body>
       <div id="main" class="test1 test2" style="color: red">111111</div>
    </body>
    </html>
    

    4.html标签的类型

    <!DOCTYPE html>
    <html>
    <head lang="en">
        <meta charset="UTF-8">
        <title></title>
        <style>
            /*块级标签*/
            div{
                background-color: red;
                width: 200px;
                height: 180px;
                /*隐藏*/
                /*display: none;*/
                /*display: inline;*/
    
                display: inline-block;
            }
    
            /*p{*/
                /*background-color: yellow;*/
                /*width: 200px;*/
                /*height: 50px;*/
            /*}*/
    
           /*行内标签*/
            span{
               background-color: yellow;
               /*让行内标签变成块级标签*/
               /*display: block;*/
               /*width: 200px;*/
               /*height: 50px;*/
            }
    
            /* 行内-块级标签*/
            input{
               width: 200px;
               height: 300px;
            }
        </style>
    </head>
    <body>
      <div>11111111</div>
      <div>11111111</div>
      <div>11111111</div>
    
      <span>22222222</span>
      <span>22222222</span>
      <span>22222222</span>
    
      <a href="#">百度一下</a>
      <a href="#">百度一下</a>
      <a href="#">百度一下</a><br><br><br>
      <!--<p>22222</p>-->
    
      <input>
      <input>
      <input>
    
    </body>
    </html>
    

    5.css3新增属性

    <!DOCTYPE html>
    <html>
    <head lang="en">
        <meta charset="UTF-8">
        <title></title>
        <style>
            div{
                font-size: 30px;
                width: 150px;
                background-color: red;
                margin: 20px;
                /*设置不透明度*/
                /*opacity: 0.2;*/
                /*box-shadow: 4px 14px 20px black;*/
            }
            /*设置透明度:红色 绿色 蓝色 透明度*/
            .test1{
               background-color: rgba(255,0,0,1.0);
            }
            .test2{
               background-color: rgba(255,0,0,0.8);
            }
            .test3{
               background-color: rgba(255,0,0,0.6);
            }
            .test4{
               background-color: rgba(255,0,0,0.4);
            }
            .test5{
               background-color: rgba(255,0,0,0.2);
            }
    
            p{
                font-size: 50px;
                color: red;
                /*设置文字阴影, 水平方向  垂直方向 模糊 颜色*/
                text-shadow: 5px 5px 10px green;
            }
    
            .test6{
                background-color: red;
                width: 400px;
                height: 250px;
                border: 20px solid green;
                /*设置圆角*/
                /*border-radius: 40px;*/
                border-top-left-radius: 90px;
                border-bottom-left-radius:100px;
            }
        </style>
    </head>
    <body>
       <div class="test1">111</div>
       <div class="test2">222</div>
       <div class="test3">333</div>
       <div class="test4">444</div>
       <div class="test5">555</div>
    
       <p>小码哥</p>
    
       <div class="test6">
           dewhdewjhdhjew
       </div>
    </body>
    </html>
    

    6.css的常用属性

    <!DOCTYPE html>
    <html>
    <head lang="en">
        <meta charset="UTF-8">
        <title></title>
        <style>
            body{
                /*设置字体大小*/
                font-size: 30px;
                /*设置文字颜色*/
                color: red;
                /*字体加粗*/
                font-weight: bolder;
            }
    
            div{
                /*复合属性,可用于设置颜色和图片*/
                background: url("img/7.jpg");
                /*设置背景的尺寸, cover跟随标签的尺寸显示*/
                background-size: cover;
                width: 300px;
                height: 300px;
    
                /*水平居中,取值:left right center*/
                text-align: center;
                /*都是隐藏内容,区别:
                1.display会连同尺寸一起隐藏
                2.visibility不会隐藏尺寸
                */
                display: none;
                visibility: hidden;
                /*设置光标的显示类型: crosshair pointer*/
                cursor: pointer;
            }
    
            span{
                /*背景颜色*/
                background-color: blue;
                /*宽度*/
                width: 300px;
                /*高度*/
                height: 200px;
                /*行高,用于垂直居中*/
                line-height: 300px;
    
            }
    
            a{
                /*设置去除下划线,用于a标签*/
                text-decoration: none;
            }
    
            .one{
                /*设置缩进: % */
               text-indent: 3%;
            }
    
            ul{
                /*设置列表的类型: none  square*/
               list-style:square;
            }
    
            #main{
                /*设置背景颜色*/
                background-color: red;
                /*设置宽度*/
                width: 90px;
                /*设置高度*/
                height: 120px;
                /* 超出标签的内容处理:hidden, auto */
                overflow: hidden;
            }
        </style>
    </head>
    <body>
      <!--<div>111111</div>-->
      <!--<span>2222222</span>-->
      <!--<p>33333333333</p>-->
    
      <div>
          <span>12112323322332</span>
      </div>
      <p class="one">21323243423434efwqewqfewqfewqfewq</p>
      <p>21323243423434fewqfewqfew</p>
      <p>21323243423434fewfew</p>
      <p>fewfewfewfewefw</p>
    
      <a href="#">百度一下</a>
    
       <ul>
           <li>111111</li>
           <li>111111</li>
           <li>111111</li>
           <li>111111</li>
       </ul>
    
       <div id="main">44444444444444444444</div>
    </body>
    </html>
    

    7.盒子模型

    <!DOCTYPE html>
    <html>
    <head lang="en">
        <meta charset="UTF-8">
        <title></title>
        <style>
            div{
                background-color: red;
                width: 250px;
                height: 250px;
                margin: 130px;
                /*设置边框: 边框宽度 边框样式 边框颜色*/
                border: 10px solid green;
                /*内边距: 上右下左*/
                padding:20px 40px 100px 20px;
            }
        </style>
    </head>
    <body>
       <div>122112</div>
    </body>
    </html>
    

    8.居中

    <!DOCTYPE html>
    <html>
    <head lang="en">
        <meta charset="UTF-8">
        <title></title>
        <!--
          标签水平居中:
             行内标签, 行内块级标签:  text-align: center;
             块级标签:  margin: 0px auto;
    
          标签垂直居中:
              line-height: 400px;
        -->
        <style>
            .test1{
                background-color: red;
                width: 300px;
                height: 400px;
                text-align: center;
                line-height: 400px;
            }
    
            span{
                background-color: purple;
            }
    
            .test2{
                background-color: green;
                width: 90px;
                /*margin-left: auto;*/
                /*margin-right: auto;*/
                margin: 0px auto;
                text-align: center;
            }
        </style>
    </head>
    <body>
       <div class="test1">
           <!--行内标签-->
           <span>12212</span>
           <!--行内-块级标签-->
           <button>百度一下</button>
           <!--块级标签-->
           <div class="test2">efwf</div>
       </div>
    </body>
    </html>
    

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        本文标题:CSS的选择器

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