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CSS实现居中效果的方法总结

目录

行内元素水平居中

text-align: center;

<style>
    .parent {
        background-color: aliceblue;
		text-align: center;
    }
    .child {
		background-color: orange;
    }
</style>
<body>
    <div class="parent">
        <span class="child">content</span>
    </div>
</body>
content

fit-content

<style>
    .parent {
        background-color: aliceblue;
        width: fit-content;
        margin: auto;
    }
    .child {
		background-color: orange;       
    }
</style>
<body>
    <div class="parent">
        <span class="child">content</span>
    </div>
</body>
content

行内元素和行内块元素垂直居中

<style>
    .parent {
        height: 200px;
        line-height: 200px;
        background-color: aliceblue;
    }
    .child {
		background-color: orange;
    }
</style>
<body>
    <div class="parent">
        <span class="child">content</span>
    </div>
</body>
content

块级元素水平居中

<style>
    .parent {
        height: 200px;
        width: 200px;
        background-color: aliceblue;
    }
    .child {
        height: 100px;
        width: 200px;
        
		background-color: orange;
    }
</style>
<body>
    <div class="parent">
        <div class="child">content</div>
    </div>
</body>
content

块级元素水平垂直居中

定位方法

方法一：必须知道宽高

<style>
    .parent {
        position: relative;
        height: 100px;
        background-color: aliceblue;
    }
    .child {
        width: 100px;
        height: 50px;
        position: absolute;
		background-color: orange;
        left: 50%;
        top: 50%;
        margin-top: -25px;
        margin-left: -50px;
    }
</style>
<body>
    <div class="parent">
        <div class="child">content</div>
    </div>
</body>
content

方法二：不必知道宽高

<style>
    .parent {
        position: relative;
        height: 100px;
        background-color: aliceblue;
    }
    .child {
        position: absolute;
		background-color: orange;
        left: 50%;
        top: 50%;
		transform: translate(-50%, -50%);
    }
</style>
<body>
    <div class="parent">
        <div class="child">content</div>
    </div>
</body>
content

方法三：margin配合定位

当我们给子元素绝对定位后，当我们给各边界距离都为0后，子元素就会填充父元素的所有可用空间，这样一来，在水平和垂直方向上就有了可以分配的空间，这时设置margin: auto;就可以自动居中。

<style>
    .parent {
        position: relative;
        height: 100px;
        background-color: aliceblue;
    }
    .child {
        position: absolute;
		background-color: orange;
        left: 0;
        top: 0;
        right: 0;
        bottom: 0;
		margin: auto;
    }
</style>
<body>
    <div class="parent">
        <div class="child">content</div>
    </div>
</body>
content

padding 方法

方法一：给父元素加 padding

<style>
    .parent {
        background-color: aliceblue;
        padding: 20px;
    }
    .child {
        height: 100px;
		background-color: orange;
    }
</style>
<body>
    <div class="parent">
        <div class="child">content</div>
    </div>
</body>
content

方法二：给子元素加 padding

<style>
    .parent {
        background-color: aliceblue;
        width: 200px;
        height: 100px;
    }
    .child {
        width: 100px;
        height: 50px;
		background-color: orange;
        padding: 25px 50px;
        background-clip: content-box;
    }
</style>
<body>
    <div class="parent">
        <div class="child">content</div>
    </div>
</body>
content

flex 布局方法

justify-content: center;控制水平居中

align-items: center;控制垂直居中

<style>
    .parent {
        height: 200px;
        background-color: aliceblue;
		display: flex;
        align-items: center;
        justify-content: center;
    }
    .child {
        height: 50px;
        width: 100px;
		background-color: orange;
    }
</style>
<body>
    <div class="parent">
        <div class="child">content</div>
    </div>
</body>
content

伪元素方法

<style>
    .parent {
        height: 100px;
        text-align: center;
        background-color: aliceblue;
    }
    .child {
        height: 50px;
        width: 100px;
        display: inline-block;
		background-color: orange;
        vertical-align: center;
    }
    .parent::before {
        content: "";
        height: 100px;
        display: inline-block;
        vertical-align: middle;
        background-color: yellow;
    }
</style>
<body>
    <div class="parent">
        <div class="child">content</div>
    </div>
</body>
content

为了方便观察，这里效果中给模拟的伪元素增加了5px的宽度，实际不用给伪元素设置宽度。

posted @ 2022-07-03 14:24  brokyz  阅读(175)  评论(0)  编辑  收藏  举报