• 前端 CSS的选择器 伪类选择器 CSS3 nth-child()


    first-child 选中第一个标签 应用CSS样式

    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta http-equiv="x-ua-compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1">
        <title>Title</title>
        <style type="text/css">
    
            /* 选中第一个标签 */
            .box ul li:first-child{
                color: red;
            }
        </style>
    </head>
    <body>
        <div class="box">
            <ul>
                <li class="item1">
                    1
                    <a href="#">jack</a>
                </li>
                <li class="item2">
                    2
                    <a href="#">ben</a>
                </li>
                <li class="item3">
                    3
                    <a href="#">peter</a>
                </li>
            </ul>
        </div>
    </body>
    </html>

    last-child 选中最后一个标签 应用CSS样式

    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta http-equiv="x-ua-compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1">
        <title>Title</title>
        <style type="text/css">
    
            /* 选中最后一个标签 */
            .box ul li:last-child{
                color: red;
            }
        </style>
    </head>
    <body>
        <div class="box">
            <ul>
                <li class="item1">
                    1
                    <a href="#">jack</a>
                </li>
                <li class="item2">
                    2
                    <a href="#">ben</a>
                </li>
                <li class="item3">
                    3
                    <a href="#">peter</a>
                </li>
            </ul>
        </div>
    </body>
    </html>

    nth-child() 选中当前指定的标签,数值从1开始
    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta http-equiv="x-ua-compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1">
        <title>Title</title>
        <style type="text/css">
    
            /* 选中当前指定的标签,数值从1开始 */
            .box ul li:nth-child(2){
                color: red;
                font-size:30px;
            }
        </style>
    </head>
    <body>
        <div class="box">
            <ul>
                <li class="item1">
                    1
                    <a href="#">jack</a>
                </li>
                <li class="item2">
                    2
                    <a href="#">ben</a>
                </li>
                <li class="item3">
                    3
                    <a href="#">peter</a>
                </li>
            </ul>
        </div>
    </body>
    </html>

    选中第二个标签

     nth-child(n)
    n表示选中所有 从0开始的 0的时候表示没有选中
    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta http-equiv="x-ua-compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1">
        <title>Title</title>
        <style type="text/css">
    
            /* n表示选中所有 从0开始的 0的时候表示没有选中 */
            .box ul li:nth-child(n){
                color: red;
                font-size:30px;
            }
        </style>
    </head>
    <body>
        <div class="box">
            <ul>
                <li class="item1">
                    1
                    <a href="#">jack</a>
                </li>
                <li class="item2">
                    2
                    <a href="#">ben</a>
                </li>
                <li class="item3">
                    3
                    <a href="#">peter</a>
                </li>
            </ul>
        </div>
    </body>
    </html>
    
    

     nth-child(2n) 偶数 
    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta http-equiv="x-ua-compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1">
        <title>Title</title>
        <style type="text/css">
    
            /* 偶数 */
            .box ul li:nth-child(2n){
                color: red;
                font-size:30px;
            }
        </style>
    </head>
    <body>
        <div class="box">
            <ul>
                <li class="item1">
                    1
                    <a href="#">jack</a>
                </li>
                <li class="item2">
                    2
                    <a href="#">ben</a>
                </li>
                <li class="item3">
                    3
                    <a href="#">peter</a>
                </li>
    
                <li class="item4">
                    4
                    <a href="#">mike</a>
                </li>
    
                <li class="item5">
                    5
                    <a href="#">tom</a>
                </li>
            </ul>
        </div>
    </body>
    </html>
    
    

    nth-child(2n-1) 奇数

    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta http-equiv="x-ua-compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1">
        <title>Title</title>
        <style type="text/css">
    
            /* 奇数 */
            .box ul li:nth-child(2n-1){
                color: red;
                font-size:30px;
            }
        </style>
    </head>
    <body>
        <div class="box">
            <ul>
                <li class="item1">
                    1
                    <a href="#">jack</a>
                </li>
                <li class="item2">
                    2
                    <a href="#">ben</a>
                </li>
                <li class="item3">
                    3
                    <a href="#">peter</a>
                </li>
    
                <li class="item4">
                    4
                    <a href="#">mike</a>
                </li>
    
                <li class="item5">
                    5
                    <a href="#">tom</a>
                </li>
            </ul>
        </div>
    </body>
    </html>

    隔几换色,隔行换色

    隔3换色,就是4n+1,隔4换色,就是5n+1。

    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta http-equiv="x-ua-compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1">
        <title>Title</title>
        <style type="text/css">
    
            /* 奇数 */
            .box ul li:nth-child(4n+1){
                color: red;
                font-size:30px;
            }
        </style>
    </head>
    <body>
        <div class="box">
            <ul>
                <li class="item1">
                    1
                    <a href="#">jack</a>
                </li>
                <li class="item2">
                    2
                    <a href="#">ben</a>
                </li>
                <li class="item3">
                    3
                    <a href="#">peter</a>
                </li>
    
                <li class="item4">
                    4
                    <a href="#">mike</a>
                </li>
    
                <li class="item5">
                    5
                    <a href="#">tom</a>
                </li>
    
                <li class="item6">
                    6
                    <a href="#">ken</a>
                </li>
    
                <li class="item7">
                    7
                    <a href="#">mary</a>
                </li>
    
                <li class="item8">
                    8
                    <a href="#">tony</a>
                </li>
    
                <li class="item9">
                    9
                    <a href="#">Howard</a>
                </li>
            </ul>
        </div>
    </body>
    </html>

    
    
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  • 原文地址:https://www.cnblogs.com/mingerlcm/p/10801198.html
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