Day15结构伪类选择器

image

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>结构伪类选择器</title>
    <style>
        li:first-child{
            background-color: red;
        }
        li:last-child{
            background-color: green;
        }
        li:nth-child(4){
            background-color: blueviolet;
        }

    </style>
</head>
<body>
    <ul>
        <li>1</li>
        <li>2</li>
        <li>3</li>
        <li>4</li>
        <li>5</li>
        <li>6</li>
        <li>7</li>
        <li>8</li>
        <li>9</li>
    </ul>
</body>
</html>

image

伪类选择器的公式

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>伪类选择器的公式写法</title>
    <style>
        /* 偶数行 */
        li:nth-child(2n){
            background-color: red;
        }
        /* 奇数行 */
        li:nth-child(2n-1){
            background-color: green;
        }
        /* 5以后得行 */
        li:nth-child(n+5){
            background-color: blueviolet;
        }
        /* 5以前的行 */
        li:nth-child(-n+5){
            background-color: firebrick;
        }
        /* 2的倍数行 */
        li:nth-child(2n){
            font-size: 50px;
        }
    </style>
</head>
<body>
    <ul>
        <li>1</li>
        <li>2</li>
        <li>3</li>
        <li>4</li>
        <li>5</li>
        <li>6</li>
        <li>7</li>
        <li>8</li>
        <li>9</li>
        <li>10</li>
        <li>11</li>
        <li>12</li>
    </ul>
</body>
</html>

image

posted @ 2025-11-08 11:57  冰涿  阅读(2)  评论(0)    收藏  举报