CSS3 清除浮动

CSS3 清除浮动

基础代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        h1, body {
            margin: 0;
        }
        h1 {
            background-color: aquamarine;
        }
        div > div:nth-of-type(1) {
            width: 200px;
            height: 200px;
            background-color: antiquewhite;
        }
        div > div:nth-of-type(2) {
            width: 200px;
            height: 200px;
            background-color: aqua;
        }
        div:nth-of-type(1) {
            background-color: pink;
        }
    </style>
</head>
<body>
    <h1>Hello World</h1>
    <div>
        <div></div>
        <div></div>
    </div>
</body>
</html>
  1. 先去掉h1,和body的margin
  2. 一个没有宽高限制的盒子包裹两个固定宽高的子盒子。
  3. 让第一个去最左边，第二个去最右边
    代码如下
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        h1, body {
            margin: 0;
        }
        h1 {
            background-color: aquamarine;
        }
        div > div:nth-of-type(1) {
            /* position: absolute; */
            /* top: 0; */
            /* right: 0; */
            width: 200px;
            float: left;
            height: 200px;
            background-color: antiquewhite;
        }
        div > div:nth-of-type(2) {
            /* position: absolute; */
            /* top: 0; */
            /* left: 0; */
            float: right;
            width: 200px;
            height: 200px;
            background-color: aqua;
        }
        div:nth-of-type(1) {
            /* position: relative; */
            background-color: pink;
        }
    </style>
</head>
<body>
    <h1>Hello World</h1>
    <div>
        <div></div>
        <div></div>
    </div>
</body>
</html>

可以看到因为子容器脱离了标准流，导致父容器无法感知子容器的高度，而高度为0.

清除浮动代码

/* 清除浮动代码 */
.clearfix:before,
.clearfix:after {
	content: "";
	display: table;
}
.clearfix::after {
	clear: both;
}
/* 用来兼容IE */
.clearfix {
	zoom: 1;
}

或者更简洁的做法

.clearfix::after {
	content: "";
	display: table;
	clear: both;
}

或者更加现代的做法，但是不支持IE

.clearfix {
	display: flow-root;
}

使用相对布局

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        h1, body {
            margin: 0;
        }
        h1 {
            background-color: aquamarine;
        }
        div > div:nth-of-type(1) {
            position: absolute;
            top: 0;
            right: 0;
            width: 200px;
            height: 200px;
            background-color: antiquewhite;
        }
        div > div:nth-of-type(2) {
            position: absolute;
            top: 0;
            left: 0;
            width: 200px;
            height: 200px;
            background-color: aqua;
        }
        div:nth-of-type(1) {
            position: relative;
            background-color: pink;
        }
    </style>
</head>
<body>
    <h1>Hello World</h1>
    <div>
        <div></div>
        <div></div>
    </div>
</body>
</html>

子元素同意脱离标准流，但是暂时不知道如何使父元素包裹子元素。

posted @ 2025-06-19 22:12  爱情丶眨眼而去  阅读(16)  评论(0)    收藏  举报