CSS处理页面元素浮动的几个办法

news2024/9/17 7:40:07

CSS处理页面元素浮动的几个办法

不使用浮动的情况下，子盒子1和2分别在盒子1中占据一行的空间。

<!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=1.0">
    <title>未使用浮动</title>
    <style>
        .box1 {
            height: 200px;
            width: 600px;
            background-color: pink;
        }

        .box2 {
            width: 600px;
            height: 240px;
            background-color: purple;
        }

        .son1 {
            width: 150px;
            height: 100px;
            background-color: skyblue;
        }

        .son2 {
            width: 300px;
            height: 100px;
            background-color: hotpink;
        }
    </style>
</head>
<body>
    <div class="box1">
        <div class="son1"></div>
        <div class="son2"></div>
    </div>
    <div class="box2"></div>
</body>
</html>

使用添加额外标签的方法清除浮动，子盒子1和2分别使用左浮动，两个元素都不占用原来文档流的空间了，跑到了同一行，额外添加一个div标签，清除浮动，避免盒子2也随着向上占据盒子1的空间。

<!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=1.0">
    <title>清除浮动 - 额外标签</title>
    <style>
        .box1 {
            /* height: 200px; 很多情况下，不方便给父级盒子高度，考虑到孩子高度会变化 */
            width: 600px;
            background-color: pink;
        }

        .box2 {
            width: 600px;
            height: 240px;
            background-color: purple;
        }

        .son1 {
            width: 150px;
            height: 100px;
            background-color: skyblue;
            float: left;
        }

        .son2 {
            width: 300px;
            height: 100px;
            background-color: hotpink;
            float: left;
        }

        .clearfix {
            clear: both;
        }
    </style>
</head>
<body>
    <div class="box1">
        <div class="son1"></div>
        <div class="son2"></div>
        <div class="clearfix"></div>
    </div>
    <div class="box2"></div>
</body>
</html>

使用双伪元素的方式清除浮动

<!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=1.0">
    <title>清除浮动 - 双伪元素</title>
    <style>
        .box1 {            
            width: 600px;
            background-color: pink;
        }

        .box2 {
            width: 600px;
            height: 240px;
            background-color: purple;
        }

        .son1 {
            width: 150px;
            height: 100px;
            background-color: skyblue;
            float: left;
        }

        .son2 {
            width: 300px;
            height: 100px;
            background-color: hotpink;
            float: left;
        }

        .clearfix:before, .clearfix:after {
            content: "";
            /* 触发BFC 防止外边距合并 */
            display: table;
        }

        .clearfix:after {
            clear: both;
        }
    </style>
</head>
<body>
    <div class="box1 clearfix">
        <div class="son1"></div>
        <div class="son2"></div>
    </div>
    <div class="box2"></div>
</body>
</html>

使用after伪元素的方式清除浮动

<!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=1.0">
    <title>清除浮动 - after伪元素</title>
    <style>
        .box1 {            
            width: 600px;
            background-color: pink;
        }

        .box2 {
            width: 600px;
            height: 240px;
            background-color: purple;
        }

        .son1 {
            width: 150px;
            height: 100px;
            background-color: skyblue;
            float: left;
        }

        .son2 {
            width: 300px;
            height: 100px;
            background-color: hotpink;
            float: left;
        }

        .clearfix:after {
            /* 内容为小点，尽量加不要空，否则低版本浏览器有空隙 */
            content: ".";
            display: block;
            height: 0;
            /* 隐藏盒子 */
            visibility: hidden;
            clear: both;
        }

        .clearfix {
            *zoom: 1;
        }
    </style>
</head>
<body>
    <div class="box1 clearfix">
        <div class="son1"></div>
        <div class="son2"></div>
    </div>
    <div class="box2"></div>
</body>
</html>

使用父级元素的overflow属性清除浮动，盒子1设置overflow为hidden，触发BFC达到清除浮动的目的。

<!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=1.0">
    <title>清除浮动 - 父级overflow</title>
    <style>
        .box1 {
            width: 600px;
            background-color: pink;
            /* 触发BFC BFC可以清除浮动 */
            overflow: hidden; 
        }

        .box2 {
            width: 600px;
            height: 240px;
            background-color: purple;
        }

        .son1 {
            width: 150px;
            height: 100px;
            background-color: skyblue;
            float: left;
        }

        .son2 {
            width: 300px;
            height: 100px;
            background-color: hotpink;
            float: left;
        }
    </style>
</head>
<body>
    <div class="box1">
        <div class="son1"></div>
        <div class="son2"></div>
    </div>
    <div class="box2"></div>
</body>
</html>